<PAGE>   1
                                                                   EXHIBIT 10.34



                             OFFICE BUILDING LEASE


                                      FOR

                   NET 2000 COMMUNICATIONS REAL ESTATE, INC.

                             TYSONS DULLES PLAZA II

                               SUITES 400 AND 410

                             McLEAN, VIRGINIA 22102







                                CHARLES E. SMITH
                           REAL ESTATE SERVICES L.P.
                               2345 CRYSTAL DRIVE
                                 CRYSTAL CITY
                              ARLINGTON, VA  22202



                                  [SMITH LOGO]
                           CHARLES E. SMITH COMPANIES
<PAGE>   2
                               TABLE OF CONTENTS
-------------------------------------------------------------------------------

                        SPECIFIC AND GENERAL PROVISIONS


                                                                          PAGE

1. SPECIFIC PROVISIONS ...................................................  1

2. RENT ..................................................................  4
   2.1  Base Annual Rent .................................................  4
        (a) Payment of Base Annual Rent ..................................  4
        (b) Escalation of Base Annual Report .............................  4
   2.2  Additional Rent ..................................................  4
        (a) Real Estate Taxes ............................................  4
        (b) Operating Expenses ...........................................  5
   2.3  Additional Rent Estimates and Adjustments ........................  5
        (a) Initial Additional Rent Adjustments...........................  5
        (b) Annual Budget ................................................  5
        (c) Additional Rent Reconciliations ..............................  5
        (d) Verification of Additional Rent ..............................  6
        (e) Fiscal Year ..................................................  6
   2.4  Rent Adjustment Limit ............................................  6
   2.5  Survival of Rent Obligation ......................................  6
   2.6  Pro Rata Share ...................................................  6
   2.7  Prorated Rent ....................................................  6
   2.8  Application of Rent ..............................................  6
   2.9  Late Payment Fee and Interest Charge .............................  6
   2.10 Other Tenant Costs and Expenses ..................................  6

3. CONSTRUCTION OF PREMISES AND OCCUPANCY ................................  6
   3.1  Tenant Plans, Construction and Rent Liability ....................  6
        (a) Preparation of Tenant Plans ..................................  6
        (b) Extension of Construction Timetable ..........................  7
        (c) Substantial Completion .......................................  7
   3.2  Possession .......................................................  7
   3.3  Permits ..........................................................  7
   3.4  Demised Premises .................................................  7

4. SUBLETTING AND ASSIGNMENT .............................................  8
   4.1  Consent ..........................................................  8
   4.2  Recapture of Premises ............................................  8
   4.3  Excess Rent and Other Consideration. .............................  8
   4.4  Tenant Liability .................................................  8
   4.5  Reasonable Standards of Consent ..................................  8
   4.6  Other Transfers ..................................................  9
   4.7  Rights on Default ................................................  9

5. SERVICES AND UTILITIES ................................................  9
   5.1  Building Standard Services and Utilities .........................  9
   5.2  Overtime Services ................................................  9
   5.3  Excessive Usage ..................................................  9
        (a) Equipment Restrictions .......................................  9
        (b) Excess Electrical Usage ...................................... 10
        (c) Additional Utility Costs ..................................... 10
   5.4  Excessive Heat Generation ........................................ 10
   5.5  Building Security ................................................ 10
   5.6  Roof and Auxiliary Spaces ........................................ 10
   5.7  Trash Removal .................................................... 10

6. USE AND UPKEEP OF PREMISES ............................................ 10
   6.1  Use .............................................................. 10
   6.2  Illegal and Prohibited Uses ...................................... 10
   6.3  Insurance Rating ................................................. 10
   6.4  Alterations ...................................................... 11
        (a) Approval Required ............................................ 11
        (b) Alteration Requirements ...................................... 11
        (c) Removal of Leasehold Improvements and Tenant's Property ...... 11
        (d) Compliance with Laws ......................................... 11
   6.5  Maintenance by Landlord .......................................... 12
        (a) Landlord Repairs and Maintenance ............................. 12
        (b) Use of Demised Premises by Landlord .......................... 12
   6.6  Signs and Publications ........................................... 12
   6.7  Excessive Floor Load ............................................. 12
   6.8  Moving and Deliveries ............................................ 12
        (a) Prohibitions/Notices ......................................... 12
        (b) Coordination with Landlord ................................... 12
        (c) Moving Damages ............................................... 12

                                      (i)

<PAGE>   3
                               TABLE OF CONTENTS
                                  (continued)

  6.9   Rules and Regulations ...........................................  13
  6.10  Tenant Maintenance and Condition of Demised Premises Upon
        Surrender ........................................................ 13
  6.11  Tenant Property and Leasehold Improvements ......................  13
  6.12  Landlord's Right to Perform Tenant's Duties ...................... 13
  6.13  Medical Waste .................................................... 13

7. ACCESS ...............................................................  13
   7.1  Landlord's Access ...............................................  13
   7.2  Restricted Access ...............................................  13
   7.3  Tenant's Access .................................................. 13

8. LIABILITY ............................................................. 14
   8.1  Tenant's Property ................................................ 14
   8.2  Criminal Acts of Third Parties ................................... 14
   8.3  Public Liability ................................................. 14
   8.4  Construction on Contiguous Property .............................. 14
   8.5  Tenant Insurance ................................................. 14
        (a) Liability Insurance .......................................... 14
        (b) Fire and Casualty Insurance .................................. 14
        (c) Increases in Coverage ........................................ 14
        (d) Policy Requirements .......................................... 14
        (e) No Limitation of Liability ................................... 14
        (f) Waiver of Subrogation ........................................ 15
        (g) Business Interruption ........................................ 15
   8.6  Incident Reports ................................................. 15

9. DAMAGE ................................................................ 15
   9.1  Damages Caused by Tenant ......................................... 15
   9.2  Fire or Casualty Damage .......................................... 15
   9.3  Untenantability .................................................. 15
        (a) Restoration Requirements ..................................... 15
        (b) Casualty Near Expiration of Lease Term ....................... 16

10.CONDEMNATION .......................................................... 16
   10.1  Landlord's Right to Award ....................................... 16
   10.2  Tenant's Right to File Claim .................................... 16

11.BANKRUPTCY ............................................................ 16
   11.1  Events of Bankruptcy ............................................ 16
   11.2  Landlord's Remedies ............................................. 16
         (a) Termination of Lease ........................................ 16
         (b) Suit for Possession ......................................... 17
         (c) Non-Exclusive Remedies ...................................... 17
         (d) Assumption or Assignment by Trustee ......................... 17
         (e) Adequate Assurance of Future Performance .................... 17
         (f) Failure to Provide Adequate Assurance ....................... 17
   11.3  Gurantors ....................................................... 17
   11.4  Damages ......................................................... 17

12.DEFAULTS AND REMEDIES ................................................. 17
   12.1  Default ......................................................... 17
   12.2  Remedies ........................................................ 17
   12.3  Landlord's Right to Relet ....................................... 18
   12.4  Recovery of Damages ............................................. 18
         (a) Quantification of Damages ................................... 18
         (b) Non-Exclusive Rights ........................................ 19
   12.5  Waiver .......................................................... 19
   12.6  Anticipatory Repudiation ........................................ 19
         (a) Repudiation Prior to Commencement Date ...................... 19
         (b) Repudiation of Any Obligation of Tenant During Lease Term ... 19
   12.7  Tenant Abandonment of Demised Premises .......................... 19
         (a) Abandonment ................................................. 19
         (b) Landlord Right to Enter and to Relet ........................ 19
   12.8  Tenant's Property ............................................... 19
   12.9  Landlord's Lien ................................................. 20
         (a) Right of Distress/Landlord's Lien ........................... 20
         (b) UCC Security Interest ....................................... 20
         (c) UCC Remedies Not Mandatory .................................. 20
  12.10  Injunctive Relief ............................................... 20
  12.11  Independent Covenants ........................................... 20

                                      (ii)

<PAGE>   4
                               TABLE OF CONTENTS
                                  (continued)


    12.12  Waiver of Redemption ........................................... 20
    12.13  Attorneys' Fees ................................................ 20

13. SUBORDINATION ......................................................... 21
    13.1  Subordination ............ ...................................... 21
    13.2  Estoppel Certificates ........................................... 21
    13.3  Attornment ...................................................... 21
    13.4  Mortgagee Rights ................................................ 21
         (a) Mortgagee Rights ............................................. 21
         (b) Notices to Mortgagee ......................................... 22

14. TENANT'S HOLDOVER ..................................................... 22
    14.1  With Landlord Consent ........................................... 22
    14.2  Without Landlord Consent ........................................ 22
15. SECURITY DEPOSIT ...................................................... 22

16. QUIET ENJOYMENT ....................................................... 23

17. SUCCESSORS ............................................................ 23

18. WAIVER OF JURY TRIAL AND STATUTE OF LIMITATIONS ....................... 23

19. LIMITATION OF LANDLORD'S LIABILITY; NOTICE ............................ 23
    19.1  Landlord's Consent .............................................. 23
    19.2  Individual Liability ............................................ 23
    19.3  Notice in Event of Landlord's Default ........................... 23

20. AUTHORITY ............................................................. 23

21. TENANT'S RESPONSIBILITY REGARDING HAZARDOUS SUBSTANCES ................ 23
    21.1  Hazardous Substances ............................................ 23
    21.2  Tenant's Restrictions ........................................... 24
          (a) Violations .................................................. 24
          (b) Use ......................................................... 24
    21.3  Affirmative Obligations ......................................... 24
          (a) Compliance with Laws ........................................ 24
          (b) Clean-Up Plans .............................................. 24
          (c) Information Requests ........................................ 24
    21.4  Tenant's Indemnity .............................................. 24
    21.5  Survival of Obligations ......................................... 24

22. JOINT AND SEVERAL LIABILITY ........................................... 24

23. DEFINITIONS ........................................................... 25
    23.1  Pronouns ........................................................ 25
    23.2  Demised Premises ................................................ 25
    23.3  Lease Term ...................................................... 25
    23.4  Tenant's Property ............................................... 25
    23.5  Leasehold Improvements .......................................... 25

24. NOTICE TO PARTIES ..................................................... 25
    24.1  Addresses for Notices ........................................... 25
    24.2  Effective Date of Notice ........................................ 25

25. NOTICE TO MORTGAGEES .................................................. 25

26. SPECIAL PROVISIONS; EXHIBITS .......................................... 25
    26.1  Incorporation in Lease .......................................... 25
    26.2  Conflicts ....................................................... 25

27. CAPTIONS .............................................................. 25

28. ENTIRE AGREEMENT; MODIFICATION ........................................ 25

29. GOVERNING LAW; SEVERABILITY ........................................... 26

30. BINDING EFFECT OF LEASE ............................................... 26

31. FORCE MAJEURE ......................................................... 26

32. RECORDATION ........................................................... 26

33. TIME OF ESSENCE ....................................................... 26

34. BROKERS ............................................................... 26

35  RELATIONSHIP OF LANDLORD AND TENANT ................................... 26

                                     (iii)
<PAGE>   5
      This Lease, made this 11th day of October  , 2000, between CESC TYSONS
DULLES PLAZA L.L.C., a Delaware limited liability company (hereinafter referred
to as "Landlord"), and NET 2000 COMMUNICATIONS REAL ESTATE, INC., a Delaware
corporation (hereinafter referred to as "Tenant").

      Landlord, for and in consideration of the covenants and agreements set
forth hereinafter, leases to Tenant, and Tenant leases from Landlord, the
premises described, for the use set forth and for the term and at the rent
reserved herein.

1.    SPECIFIC PROVISIONS

      1.1   PREMISES



            (a)  DEMISED PREMISES:  Suite 400, consisting of 12,513 square feet
                                    and Suite 410, consisting of 14,162 square
                                    feet.

            (b)  RENTABLE AREA:     Approximately 26,675 square feet (Modified
                                    Washington D.C. Association of Realtors
                                    standard floor area measure as defined in
                                    Exhibit G).

            (c)  COMPLEX:           The buildings, improvements and grounds
                                    known as Tysons Dulles Plaza, of which the
                                    Building is a part.

            (d)  BUILDING:          TYSONS DULLES PLAZA II

            (e)  ADDRESS:           1430 Spring Hill Road
                                    McLean, Virginia 22102

      1.2   LEASE DATES


            (a)   LEASE TERM:       The term of this Lease ("Lease Term") shall
                                    be Ten (10) years, commencing on November 1,
                                    2001 ("CommencementDate"), and expiring on
                                    October 31, 2011, both dates inclusive,
                                    unless sooner terminated in accordance with
                                    the provisions of this Lease.
                                    Notwithstanding the foregoing, the term for
                                    Suite 400 shall start on the later of
                                    January 1, 2002 or sixty (60) days after
                                    Landlord tenders possession thereof to
                                    Tenant.

            (b)   BASE YEAR:        Base Year shall be defined as the period
                                    commencing on January 1, 2001, and ending on
                                    December 31, 2001.

            (c)   FISCAL YEAR:      Fiscal Year shall be defined as each annual
                                    period, or portion thereof, included within
                                    the Lease Term commencing on January 1 and
                                    ending on December 31.

            (d)   LEASE YEAR:       The first Lease Year shall commence on the
                                    Commencement Date and shall terminate at
                                    11:59 p.m. on the day before the first
                                    anniversary of the Commencement Date. All
                                    subsequent Lease Years shall be for twelve
                                    calendar months, except that the last Lease
                                    Year shall terminate on the date this Lease
                                    expires or is terminated in accordance with
                                    the provisions hereof.

            (e)   CALENDAR YEAR:    Calendar Year (sometimes appearing as
                                    'calendar year') shall be defined as each
                                    annual period from January 1 through the
                                    immediately following December 31.




                                       1
<PAGE>   6


1.3   BASE ANNUAL RENT

      INITIAL BASE ANNUAL RENT: (i) Four Hundred Thirty-Seven Thousand Nine
      Hundred Fifty-Five and 00/100 Dollars ($437,955.00), payable in equal
      monthly installments of Thirty-Six Thousand Four Hundred Ninety-Six and
      25/100 Dollars ($36,496.25), hereinafter referred to as "base monthly
      rent", for the period November 1, 2001 through December 31, 2001; and Nine
      Hundred Thirty-Three Thousand Six Hundred Twenty-Four and 96/100 Dollars
      ($933,624.96), payable in equal monthly installments of Seventy-Seven
      Thousand Eight Hundred Two and 08/100 Dollars ($77,802.08), hereinafter
      referred to as "base monthly rent", for the period January 1, 2002
      (provided possession of Suite 400 shall have been tendered by November 1,
      2001; otherwise, the aforesaid date shall be postponed to the extent
      tender of possession was delayed) through October 31, 2002.

      (ii) Nine Hundred Sixty-One Thousand Six Hundred Thirty-Three and 68/100
      Dollars ($961,633.68), payable in equal monthly installments of Eighty
      Thousand One Hundred Thirty-Six and 14/100 Dollars ($80,136.14),
      hereinafter referred to as "base monthly rent", for the period November 1,
      2002 through October 31, 2003.

      (iii) Nine Hundred Ninety Thousand Four Hundred Eighty-Two and 64/100
      Dollars ($990,482.64), payable in equal monthly installments of Eighty-Two
      Thousand Five Hundred Forty and 22/100 Dollars ($82,540.22), hereinafter
      referred to as "base monthly rent", for the period November 1, 2003
      through October 31, 2004.

      (iv) One Million Twenty Thousand One Hundred Ninety-Seven and 16/100
      Dollars ($1,020,197.16), payable in equal monthly installments of
      Eighty-Five Thousand Sixteen and 43/100 Dollars ($85,016.43), hereinafter
      referred to as "base monthly rent", for the period November 1, 2004
      through October 31, 2005.

      (v) One Million Fifty Thousand Eight Hundred Three and 04/100 Dollars
      ($1,050,803.04), payable in equal monthly installments of Eighty-Seven
      Thousand Five Hundred Sixty-Six and 92/100 Dollars ($87,566.92),
      hereinafter referred to as "base monthly rent", for the period November 1,
      2005 through October 31, 2006.

      (vi) One Million One Hundred Thirty-Five Thousand Six Hundred
      Seventy-Seven and 12/100 Dollars ($1,135,677.12), payable in equal monthly
      installments of Ninety-Four Thousand Six Hundred Thirty-Nine and 76/100
      Dollars ($ 94,639.76), hereinafter referred to as "base monthly rent", for
      the period November 1, 2006 through October 31, 2007.

      (vii) One Million One Hundred Sixty-Nine Thousand Seven Hundred
      Forty-Seven and 40/100 Dollars ($1,169,747.40), payable in equal monthly
      installments of Ninety-Seven Thousand Four Hundred Seventy-Eight and
      95/100 Dollars ($97,478.95), hereinafter referred to as "base monthly
      rent", for the period November 1, 2007 through October 31, 2008.

      (viii) One Million Two Hundred Four Thousand Eight Hundred Thirty-Nine and
      84/100 Dollars ($1,204,839.84), payable in equal monthly installments of
      One Hundred Thousand Four Hundred Three and 32/100 Dollars ($100,403.32),
      hereinafter referred to as "base monthly rent", for the period November 1,
      2008 through October 31, 2009.

      (ix) One Million Two Hundred Forty Thousand Nine Hundred Eighty-Five and
      04/100 Dollars ($1,240,985.04), payable in equal monthly installments of
      One Hundred Three Thousand Four Hundred Fifteen and 42/100 Dollars
      ($103,415.42), hereinafter referred to as "base monthly rent", for the
      period November 1, 2009 through October 31, 2010.

      (x) One Million Two Hundred Seventy-Eight Thousand Two Hundred Fourteen
      and 56/100 Dollars ($1,278,214.56), payable in equal monthly installments
      of One Hundred Six Thousand Five Hundred Seventeen and 88/100 Dollars
      ($106,517.88), hereinafter referred to as "base monthly rent", for the
      period November 1, 2010 through October 31, 2011.

1.4   BASE YEAR COSTS

      Not Applicable.


                                        2

<PAGE>   7

1.5   ADDITIONAL RENT

      Additional Rent shall be payable by Tenant in accordance with Section 2,
      commencing on the first (1st) anniversary of the Commencement Date,
      consisting of each of the following:

      (a)   INCREASES IN REAL
            ESTATE TAXES:       Tenant's pro rata share, equal to Seventeen and
                                Twenty-Nine Hundredths Percent (17.29 %), of the
                                amount of Real Estate Taxes in excess of the
                                Base Year Real Estate Taxes.

      (b)   INCREASES IN
            OPERATING
            EXPENSES:           Tenant's pro rata share, equal to Seventeen and
                                Twenty-Nine Hundredths Percent (17.29 %), of the
                                amount of Operating Expenses in excess of the
                                Base Year Operating Expenses.

1.6   SECURITY DEPOSIT

      Seven Hundred Thousand 00/100 Dollars ($700,000.00).
      See Section 55.1 hereinafter.

1.7   STANDARD BUILDING OPERATING DAYS AND HOURS

      8:00 A.M. to 6:00 P.M. Monday - Friday
      8:00 A.M. to 1:00 P.M. Saturday

1.8   USE OF PREMISES

      General office use in keeping with the quality and nature of this first
      class office building.

 1.9  (a)   ADDRESS FOR NOTICES TO TENANT

            Net 2000 Communications Real Estate, Inc.
            1430 Spring Hill Road
            Suite 400
            McLean, VA 22102

                AND

            Net 2000 Communications Real Estate, Inc.
            2180 Fox Mill Road
            Herndon, VA 20171
            Attn: Corporate Real Estate

      (b)   ADDRESS FOR NOTICES TO LANDLORD

            CESC Tysons Dulles Plaza L.L.C.
            c/o Charles E. Smith Real Estate Services L.P.
            2345 Crystal Drive
            Arlington, VA 22202

      (c)   ADDRESS FOR PAYMENT OF RENT

            CESC Tysons Dulles Plaza L.L.C.
            c/o Charles E. Smith Real Estate Services L.P.
            P. O. Box 642006
            Pittsburgh, PA 15264-2006

                                        3


<PAGE>   8


1.10 SPECIAL PROVISIONS

<TABLE>
<S>                                                     <C>
Rent                                                    Section 36
Accrual of Rent Obligation                              Section 37
Parking                                                 Section 38
Renewal Option                                          Section 39
Landlord's Contribution                                 Section 40
Space Planning, Architectural and Engineering Plans     Section 41
Reasonableness of Landlord                              Section 42
Construction of Premises and Occupancy                  Section 43
Subletting and Assignment                               Section 44
Services and Utilities                                  Section 45
Exterior Signage                                        Section 46
Use and Upkeep of Premises                              Section 47
Access                                                  Section 48
Liability                                               Section 49
Damage                                                  Section 50
Condemnation                                            Section 51
Defaults and Remedies                                   Section 52
Subordination                                           Section 53
Tenant's Holdover                                       Section 54
Security Deposit                                        Section 55
Quiet Enjoyment                                         Section 56
Waiver of Jury Trial                                    Section 57
Limitation of Landlord's Liability; Notice              Section 58
Tenant's Responsibility Regarding Hazardous Substances  Section 59
Tenant Force Majeure                                    Section 60
Recordation                                             Section 61
Time of Essence                                         Section 62
Brokers and Commissions                                 Section 63
Exhibit C                                               Section 64
Right of First Offering                                 Section 65
Execution of Document                                   Section 66
</TABLE>


1.11 EXHIBITS TO LEASE

     Exhibit A- Not Applicable
     Exhibit B- Not Applicable
     Exhibit C- Building Rules and Regulations
     Exhibit D- Cleaning Specifications
     Exhibit E- Guaranty
     Exhibit F- Not Applicable
     Exhibit G- Rentable Area Definition


                                      3A


<PAGE>   9




      IN WITNESS WHEREOF, Landlord has caused this Lease, composed of Specific
Provisions, General Provisions, Special Provisions and Exhibits, to be signed
and sealed by one or more of its Officers, General Partners, Trustees, or
Agents, and Tenant has caused this Lease, as described above, to be signed in
its corporate name by its duly authorized officer and its corporate seal to be
hereto affixed and duly attested by its Secretary.

<TABLE>
<S>                                <C>
WITNESS:                           LANDLORD:      CESC TYSONS DULLES PLAZA L.L.C.

                                   By:   Charles E. Smith Commercial Realty L.P., a
                                         Delaware limited partnership, Sole Member

                                         By:  Charles E. Smith Commercial Realty
                                              L.L.C., a Delaware limited liability
                                              company, General Partner of Sole Member


/s/ [SIG]                                     By: /s/ KENNETH L. McVEARRY        (SEAL)
----------------------                           --------------------------------
                                                 Kenneth L. McVearry
                                                 Executive President of General
                                                 Partner of Sole Member

WITNESS:                           TENANT:       NET 2000 COMMUNICATIONS
                                                 REAL ESTATE, INC.

/s/ KELLY D. JOHNSON               BY        /s/JAMES W. MOSES                   (SEAL)
----------------------               --------------------------------------------
    KELLY D. JOHNSON                   Name: James W. Moses
                                       Title: AVP of Corporate Real Estate
</TABLE>

                                      3B
<PAGE>   10
                               GENERAL PROVISIONS


2.      RENT

     2.1     Base Annual Rent.

        (a) Payment of Base Annual Rent. Tenant shall pay the first monthly
installment of Base Annual Rent specified in Section 1.3 upon execution of this
Lease. After the Commencement Date, Tenant shall pay the remaining monthly
installments of Base Annual Rent in advance without deduction, demand, right of
set-off or recoupment, in immediately available funds, on the first day of each
and every calendar month throughout the entire Lease Term specified in Section
1.2(a), to Charles E. Smith Real Estate Services L.P. ("Landlord's Agent"), by
electronic funds transfer if requested by Landlord, or otherwise at the address
specified in Section 1.9(b) or 1.9(c), as applicable, or to such other person or
at such other place as Landlord may hereafter designate in writing.

        (b) Escalation of Base Annual Rent. Commencing on the first anniversary
date of the Commencement Date and continuing on each subsequent anniversary
thereof, the Base Annual Rent shall be increased by the Percentage Factor
stipulated in Section 1.3(b) times the Base Annual Rent payable for the
preceding Lease Year (all of which shall be calculated without giving effect to
any waiver of rent or rent credit otherwise provided to Tenant). The escalated
Base Annual Rent so determined shall be the "Base Annual Rent" for all purposes
of this Lease, including the calculation of the increase in Base Annual Rent for
the subsequent Lease Year.

     2.2     Additional Rent.  Commencing on the date set forth in Section 1.5
and continuing throughout the Lease Term, Tenant shall pay as Additional Rent
Tenant's pro rata share of any (i) Real Estate Taxes and (ii) Operating
Expenses, in excess of the (i) Real Estate Taxes and (ii) Operating Expenses,
respectively, accruing during the Base Year. Additional Rent shall be determined
as follows:

        (a) Real Estate Taxes. Tenant shall pay Tenant's pro rata share, as
defined in Section 1 .5(a), of any Real Estate Taxes accruing during each Fiscal
Year falling entirely or partly within the Lease Term, in excess of the amount
of Real Estate Taxes accruing during the Base Year.

             (i)     The term "Real Estate Taxes" shall mean (1) all taxes,
assessments (including all assessments for public improvements or benefits,
whether or not commenced or completed prior to the date hereof and whether or
not to be completed within the Lease Term), water, sewer, transportation or
other excises, levies, license fees, permit fees, impact fees, inspection fees,
and other authorization fees and other similar charges, in each case whether
general or special, levied or assessed, ordinary or extraordinary, foreseen or
unforeseen, of every character (including all interest and penalties thereon),
which at any time during or in respect of the Lease Term, may, by any
governmental or taxing authority, be assessed, levied, confirmed, or imposed on
or in respect of, or be a lien upon, the land and the building improvements of
which the Demised Premises are a part, and on any land and/or improvements now
or hereafter owned by Landlord and/or others that provide the Complex or
locality or the Demised Premises with other services, programs, amenities or
common facilities, together with (2) any other tax imposed on real estate or on
owners of real estate generally, including taxes imposed on leasehold
improvements which are assessed against the Landlord and taxes upon or with
respect to any activity conducted on the land and improvements of which the
Demised Premises are a part, upon this Lease or any rent reserved or payable
hereunder, and (3) to the extent the following taxes are in lieu of or a
substitute for any other taxes which are, or would be, payable by Landlord as
Real Estate Taxes, (a) any income, excess profits, or other taxes of Landlord
determined on the basis of its income, receipts, or revenues, (b) any estate,
inheritance, succession, gift, capital levy, or similar tax of Landlord, (c) any
franchise, capital stock, or similar taxes of Landlord and (d) any income,
excess profits, or other taxes of Landlord determined on the basis of its income
or revenue derived pursuant to this Lease,

             (ii)    If Real Estate Taxes accruing during the Base Year are
subsequently reduced by any application or proceeding brought by or on behalf of
Landlord for reduction in the amount of Real Estate Taxes payable by Landlord,
the Real Estate Taxes deemed to have accrued during the Base Year shall be
decreased and Landlord may promptly bill Tenant for the Additional Rent not
previously paid by Tenant for any Fiscal Year during the Lease Term, based upon
the reduced amount of Real Estate Taxes accruing during the Base Year.

             (iii) If the Building's occupancy level is seventy percent (70%) or
less for six (6) months or more during any Fiscal Year other than the Base Year,
or if all land and improvements upon which Real Estate Taxes are or may be
assessed pursuant to Section 2.2(a)(i) above are not fully assessed during any
portion of any Fiscal Year other than any portion of the Base Year, then the
Real Estate Taxes accruing during such Fiscal Year or portion thereof (other
than the Base Year) may be adjusted, at Landlord's sole option, to project the
Real Estate Taxes as if the Building were one hundred percent (100%) occupied
and/or all land and improvements are fully assessed during such Fiscal Year as
reasonably estimated by Landlord using standard accounting procedures so that
Tenant's share of the Real Estate Taxes is the amount which Tenant would bear if
the Building were fully occupied and/or if all land and improvements upon which
Real Estate Taxes may be assessed were fully assessed during the entire such
Fiscal Year. For example, if the occupancy rate for the Building during at least
six (6) months of a Fiscal Year is seventy percent (70%), and if the real estate
tax bill to Landlord is $240,000 based on the less-than-complete occupancy of
the Building, and if Landlord estimates that the Real Estate Taxes that would
have accrued if the Building had been one hundred percent (100%) occupied by
tenants would have been Three Hundred Thousand Dollars ($300,000), then Tenant
would pay as Additional Rent pursuant to Section 1.5(a) its pro rata share of
the amount by which $300,000 exceeds the Real Estate Taxes which accrued during
the Base Year.

             (iv) In addition to the pro rata share of any increase in Real
Estate Taxes to be paid by Tenant pursuant to Sections 2.2(a)(i), (ii) and (iii)
above, Tenant shall reimburse Landlord upon demand for any and all taxes
required to be paid by Landlord upon, measured by, or reasonably attributable to
the cost or value of Tenant's Property or by the cost or value of any Leasehold
Improvements made in or to the Demised Premises by or for Tenant, regardless of
whether title to such Leasehold Improvements shall be in Tenant or Landlord, and
for all taxes required to be paid by Landlord upon, measured by, or reasonably
attributable to or with respect to the possession, leasing, operation,
management, maintenance, alteration, repair, use or occupancy by Tenant of the
Demised Premises or any portion thereof to the extent such taxes are not
included in Real Estate Taxes.


                                       4
<PAGE>   11


        (b) Operating Expenses. Tenant shall pay Tenant's pro rata share, as
indicated in Section 1.5(b), of any Operating Expenses accruing during each
Fiscal Year falling entirely or partly within the Lease Term, in excess of the
Operating Expenses accruing during the Base Year

             (i) The term "Operating Expenses" shall mean any and all expenses
of Landlord in connection with the servicing, insuring, operation, maintenance,
replacement and repair of the Building and related interior and exterior
appurtenances of which the Demised Premises are a part, or for health, welfare
or safety; expenses, if any, of Landlord either alone or in conjunction with
others to maintain common facilities, amenities, programs and services required
or approved by jurisdictional authorities for the Building, the building site,
the Complex or the locality in which the Complex is situated; the cost of any
services to achieve a reduction of, or to minimize the increase in, Operating
Expenses or Real Estate Taxes; management fees; vault rentals; business license,
personal property and other taxes; capital expenditures and other costs of
Landlord for equipment or systems installed to reduce or minimize increases in
Operating Expenses or to comply with any governmental or quasi-governmental
ordinance or requirement (at the option of Landlord, such costs, with interest,
may be recovered from Tenant in installments simultaneous with the payment of
monthly installments of Base Annual Rent in accordance with a cost repayment
schedule based on the useful life of such equipment or systems). At the sole
discretion of Landlord, certain of these expenses may be equitably apportioned
among two or more buildings in the Complex.

             (ii) The term "Operating Expenses" shall not include any of the
following, except to the extent that such costs and expenses are specifically
included in Operating Expenses as described in Section 2.2(b)(i) above: capital
expenditures and depreciation of the Building; painting and decorating of tenant
space; interest and amortization of mortgages; ground rent; compensation paid to
officers or executives of Landlord; taxes as measured by the net income of
Landlord from the operation of the Building; insurance reimbursements of
Operating Expenses to Landlord; Real Estate Taxes; brokerage commissions; and
marketing expenses.

             (iii) If the Building's occupancy level is seventy percent (70%) or
less for six (6) months or more during any Fiscal Year other than the Base Year,
or if all land and improvements upon which Operating Expenses are calculated or
may be calculated pursuant to Section 2.2(b)(i) above were not fully complete
and operational, or if any tenant is separately paying for services or utilities
furnished to its premises or is provided with fewer services than customarily
provided for tenants of general office space in the Building, then Operating
Expenses accrued during such Fiscal Year or portion thereof (other than the Base
Year) may be adjusted, at Landlord's sole option, to include all additional
expenses, as estimated by Landlord applying standard accounting procedures, so
that Tenant's share of Operating Expenses is the amount which would have been
incurred by Tenant if the Building were fully occupied by tenants and all land
and improvements upon which Operating Expenses are calculated or may be
calculated pursuant to Section 2.2(b)(i) above were fully complete and
operational during the entire such Fiscal Year using services and utilities
customarily provided for general office use. For example, if the occupancy rate
for the Building during at least six (6) months of a Fiscal Year is seventy
percent (70%), and if the janitorial contractor charges $1.00 per square foot of
occupied rentable area per year, and if the Building contains 100,000 square
feet of rentable area, and if Landlord estimates that the Operating Expenses
that would have accrued if the Building had been one hundred percent (100%)
occupied by tenants, using such customary janitorial services during such year,
would have been $100,000, then Tenant would pay as Additional Rent pursuant to
Section 1.5(b) its pro rata share of the amount by which $100,000 exceeds the
Operating Expenses which accrued during the Base Year.

     2.3     Additional Rent Estimates and Adjustments

        (a) Initial additional Rent Adjustments. Landlord shall submit to Tenant
prior to the date set forth in Section 1.5 a statement of Landlord's reasonable
estimate of the increases described in Sections 2.2(a) and (b) above, together
with the amount of Tenant's Additional Rent which is estimated to result from
such increases, in which event Tenant shall pay such estimated Additional Rent
to Landlord in equal monthly installments beginning on the date set forth in
Section 1.5, on the dates and in the manner required for the payment of Tenant's
monthly installments of Base Annual Rent.

        (b) Annual Budget. Subsequent to the Calendar Year in which Tenant's
obligation to pay component of Additional Rent pursuant to Section 2.2
commences, Tenant shall thereafter pay each such component of Additional Rent in
twelve equal monthly installments based upon Landlord's estimates. In order to
provide for the current monthly payment of each component of Additional Rent
described herein, Landlord shall submit to Tenant a statement of Landlord's
reasonable estimate of the increases described in Section 2.2 above, together
with the amount of Tenant's Additional Rent which is estimated to result from
such increases. Tenant agrees to pay each such estimated component of Additional
Rent to Landlord in twelve equal installments beginning on January 1, on the
dates and in the manner required for the payment of Tenant's monthly
installments of Base Annual Rent.

        (c) Additional Rent Reconciliations. After the end of each Calendar
Year, Landlord will submit to Tenant an audited financial statement of the
actual increases in Real Estate Taxes and Operating Expenses accruing during the
Fiscal Year which ended during such Calendar Year over the Real Estate Taxes and
Operating Expenses which accrued during the Base Year, respectively. Such
statement shall also indicate the amount of Tenant's excess payment or
underpayment of Additional Rent based on Landlord's estimate described in
Sections 2.3(a) and 2.3(b). If Additional Rent paid by Tenant during the
preceding Calendar Year shall be in excess of, or less than, the aggregate of
its share of the actual increase in Real Estate Taxes and Operating Expenses,
Landlord and Tenant agree to make the appropriate adjustment following the
submission of Landlord's statement. Tenant shall either pay any Additional Rent
due with the installment of Base Annual Rent due for the month following
submission of Landlord's statement, or pay any Additional Rent due within thirty
(30) days if the Lease Term has expired or has otherwise been terminated. Tenant
shall deduct its excess payment, if any, from the installment of Base Annual
Rent due for the month following submission of Landlord's statement, or
following the expiration or earlier termination of the Lease Term, Tenant shall
be reimbursed for any excess payments made, less any amounts then due Landlord
under this Lease, upon demand.

                                       5


<PAGE>   12

        (d) Verification of Additional Rent. Unless Tenant asserts specific
errors within thirty (30) days after Landlord has submitted the audited
financial statement for a Fiscal Year to Tenant, Tenant shall have no right to
contest the amount of Tenant's pro rata share of Real Estate Taxes and/or
Operating Expenses or the statement submitted by Landlord. No such assertion of
error by Tenant shall extend the time for payments as set forth in Sections 2.2
and 2.3 above. If Tenant has given a timely assertion of error and if it shall
be determined by Landlord there is an error in Landlord's statement, Tenant
shall be entitled to a credit for any overpayment, which shall be applied to any
sums then due Landlord under this Lease and then to the next installment(s) of
Additional Rent until fully credited for the overpayment, or refunded if Tenant
has vacated the Demised Premises, or Tenant shall be billed for any underpayment
and shall remit any amount owing to Landlord within ten (10) business days of
Tenant's receipt of such statement.

        (e) Fiscal Year. Landlord shall have the right to change its Fiscal Year
from time to time. If Landlord changes its Fiscal Year during the Lease Term,
thereby creating a Fiscal Year with fewer than twelve (12) months (hereinafter
"short year"), the Real Estate Taxes and Operating Expenses for the short year
shall be determined on an annualized basis by taking the monthly average of the
actual Real Estate Taxes and Operating Expenses, respectively, and multiplying
each by twelve. The amounts determined by this method shall be used in
determining the increases described in Sections 2.2(a) and 2.2(b) for the short
year.

     2.4     Rent Adjustment Limit. Notwithstanding any deductions from or
adjustments to Base Annual Rent and Additional Rent as provided for above, in no
event shall the total monthly installment of Base Annual Rent and Additional
Rent to be paid by Tenant in any month during the Lease Term or any extension
thereof be less than the monthly installment of Base Annual Rent stipulated in
Section 1.3, except as required as the result of the Landlord's application of a
credit due to Tenant pursuant to Section 2.3(c).

     2.5     Survival of Rent Obligation. The obligation of Tenant with
respect to payment of Base Annual Rent, as defined in Section 2.1, and
Additional Rent as defined in Sections 2.2 and 2.10, together with all other
sums due hereunder, accrued and unpaid during the Lease Term, shall survive the
expiration or earlier termination of this Lease.

     2.6     Pro Rata Share. Tenant's "pro rata share" stipulated in Sections
1.5(a) and 1.5(b) represent the ratio that the total rentable area of the
Demised Premises bears to the total rentable area of the Building. In the event
of any dispute as to the Tenant's "pro rata share", certification of the "pro
rata share" by Landlord's architect shall be binding on both Landlord and
Tenant.

     2.7     Prorated Rent. Any Base Annual Rent or Additional Rent payable
pursuant to Sections 2.1 and 2.2 for one or more full calendar months in a
partial Fiscal Year at the beginning or end of the Lease Term shall be prorated
based upon the number of months in the Fiscal Year. Any Base Annual Rent or
Additional Rent payable pursuant to Sections 2.1 and 2.2 for a portion of a
calendar month shall be prorated based upon the number of days in the applicable
calendar month.

     2.8     Application of Rent. No payment by Tenant or receipt by Landlord
of lesser amounts of Base Annual Rent or Additional Rent than those required by
this Lease shall be deemed to be other than on account of the earliest unpaid
stipulated Base Annual Rent or Additional Rent. No endorsement or statement on
any check or any letter accompanying any check or payment as Base Annual Rent or
Additional Rent shall be deemed an accord and satisfaction, and Landlord may
accept such check or payment without prejudice to Landlord's right to recover
the balance of such Base Annual Rent and Additional Rent or pursue any other
remedy provided in this Lease. Any credit due to Tenant hereunder by reason of
overpayment of Base Annual Rent or Additional Rent shall first be applied to any
Base Annual Rent, Additional Rent or other sums owed to Landlord by Tenant as
set forth elsewhere in this Lease or if Tenant shall be in default when said
credit shall be owed.

     2.9     Late Payment Fee and Interest Charge. In the event any
installment of Base Annual Rent or Additional Rent due hereunder is not paid
within ten (10) calendar days after it is due, then Tenant shall also pay to
Landlord as Additional Rent (a) a late payment fee equal to five percent (5%) of
the payment as liquidated damages for the additional administrative costs
incurred by Landlord as a result of such late payments, plus (b) an interest
charge calculated at the rate of eighteen percent (18%) per annum on the
delinquent payment from the date due until paid.

    2.10    Other Tenant Cost and Expenses. All costs and expenses which
Tenant assumes or agrees to pay to Landlord pursuant to this Lease, including
without limitation costs of construction and alterations, shall be deemed
Additional Rent, whether or not the same is specifically designated herein as
Additional Rent, and, in the event of nonpayment thereof, Landlord shall have
all the rights and remedies herein provided for the nonpayment of Base Annual
Rent and Additional Rent payable pursuant to Sections 2.1 and 2.2, including
assessment of late payment fees and interest charges.

3.     CONSTRUCTION OF PREMISES AND OCCUPANCY

     3.1     Tenant Plans, Construction and Rent Liability. Exhibit F attached
to this Lease, describes the obligations of Landlord and Tenant, and the
respective time periods for performance thereof, for the preparation and
approval of construction plans, cost estimates, working drawings and completion
of improvements and fixturing for occupancy. The improvements to be constructed
by Landlord in the Demised Premises are hereinafter referred to as the
"Construction Improvements". Said time periods shall apply irrespective of
whether Tenant uses the architect, engineer and/or general contractor selected
by Landlord, or firms of Tenant's own selection. The Tenant shall deliver to
Landlord, by the date specified on Exhibit F, a preliminary plan approved in
writing by the Tenant showing Tenant's partition, electrical and telephone
requirements, planned occupancy numbers and distribution within the Demised
Premises, and all other requirements otherwise deemed necessary by the Landlord
for the preparation of the working drawings and cost estimate.

        (a) Preparation of Tenant Plans.

             (i)     If Tenant uses architects and engineers selected by
Landlord, Landlord shall pay for preparation of the first preliminary plan (and
one revision) specified on Exhibit F, and the first set of working drawings (and
one set of revisions) for building standard design features (as defined in the
Outline Specifications, if any, attached hereto and made a part hereof as
Exhibit B, and applicable to first generation space only) or for design features
to be built at Landlord's expense (applicable to space other than first
generation space); all subsequent revisions of preliminary plans and working
drawings, plus the cost of all design work related to above building standard
design features and for design features not to be built at Landlord's expense,
as applicable, shall be at Tenant's expense.


                                       6
<PAGE>   13



                (ii)    If Tenant's architect or engineer prepares the
preliminary plan, the preliminary plan and all revisions thereto shall be at
Tenant's expense. Landlord shall pay for one set of working drawings for
building standard design features (applicable to first-generation space) or for
design features to be built at Landlord's expense (applicable to space other
than first-generation space) and one cost estimate. All design work related to
above building standard design features and to design features not to be built
at Landlord's expense and all subsequent revisions to drawings and estimates
shall be at Tenant's expense. Landlord shall have the right to approve any
architect and/or engineer selected by Tenant, which approval shall not be
unreasonably withheld, and each of Tenant's architects and engineers shall be
licensed in the jurisdiction in which the Demised Premises are located and
shall maintain (and provide Landlord with evidence of the existence of)
professional liability insurance adequate in Landlord's reasonable judgment.

                (iii)   Tenant's preliminary plan, whether prepared by an
architect or engineer selected by Landlord or by Tenant's architect or engineer,
shall provide sufficient information to permit Landlord to have working drawings
and cost estimate prepared. Tenant's preliminary plan shall be certified by the
architect or engineer preparing same to be in compliance with applicable
building and fire codes, and with The Americans with Disabilities Act and all
amendments, modifications, extensions, replacements, regulations, orders and
directives in connection therewith (the "ADA"). If the Demised Premises as
reflected on Tenant's plans are not in compliance with applicable building and
fire codes, or do not comply with all requirements of the ADA, then Tenant's
plans shall not be, nor shall they be deemed to be, acceptable to Landlord.
Landlord's approval of Tenant's plans or work does not constitute certification
by Landlord that said plans or work meet the applicable requirements of any
building or fire codes, laws or regulations, or the ADA, nor shall it impose any
liability whatsoever upon Landlord, If Tenant's preliminary plans are acceptable
to Landlord, Landlord shall have working drawings prepared within the time
period set forth on Exhibit F, and when the working drawings are completed by
the architect and engineer, the Tenant shall approve in writing both the working
drawings and Landlord's final cost estimate within the number of working days
stipulated on Exhibit F. Tenant's failure to approve or disapprove any estimates
or plans within the time periods set forth on Exhibit F shall be deemed to
constitute approval for purposes of this Section.

        (b)     Extension of Construction Timetable. Nothing contained in this
Section 3.1, nor any delay in completing the Demised Premises, shall in any
manner affect the Commencement Date set forth in Section 1.2 or Tenant's
liability for payment of Base Annual Rent and Additional Rent from such
Commencement Date, except as follows. If Landlord requires longer than the
number of working days stipulated on Exhibit F to prepare working drawings and
prepare the cost estimate following receipt of Tenant's approved preliminary
plan, or if Landlord requires longer than the number of working days stipulated
on Exhibit F to substantially complete Construction Improvements in the Demised
Premises after the final working drawings and cost estimate have been approved
by the Tenant in writing, then the Commencement Date shall be postponed by one
day for each extra day Landlord requires for the foregoing preparation of
working drawings and cost estimate and/or substantial completion of Construction
Improvements, as the case may be, which postponement shall be Tenant's sole and
exclusive remedy. In the event Tenant delays approval of either the preliminary
plan, the working drawings and/or the final cost estimate or makes changes in
the work after approval of working drawings and the final cost estimate, or
Tenant's contractors interfere with Landlord's work, thereby delaying
substantial completion and Landlord's tender of possession of the Demised
Premises to Tenant, Tenant shall nevertheless remain liable for the payment of
Base Annual Rent and Additional Rent from the Commencement Date specified in
Section 1.2. Time is of the essence as to the Tenant's performance within the
time periods specified for approval of plans and cost estimates set forth on
Exhibit F pursuant to this Section 3.1.

        (c)     Substantial Completion. For the purposes of this Section 3.1,
"substantial completion" of the Construction Improvements shall mean when all
work to be performed by Landlord pursuant to the approved working drawings and
final cost estimate has been completed, except for minor items of work and minor
adjustments of equipment and fixtures that can be completed after occupancy of
the Demised Premises without causing material interference with Tenant's
reasonable use of the Demised Premises (i.e., "punch-list" items) in accordance
with the "use of the premises" as defined in Section 1.8. In the event Tenant's
plans specify any Construction Improvements that are not building standard, or
are not immediately available in the metropolitan Washington, D.C., area within
the time period for construction set forth on Exhibit F, the delivery and
installation of which precludes Landlord from substantially completing the
Construction Improvements in the Demised Premises by the Commencement Date
specified in Section 1.2, Tenant shall nevertheless remain liable for the
payment of Base Annual Rent and Additional Rent from such Commencement Date.

   3.2  Possession. If Landlord shall be unable to tender possession of the
Demised Premises on the Commencement Date set forth in Section 1.2 by reason of:
(a) the fact that the Demised Premises are located in a building being
constructed and which has not been sufficiently completed to make the Demised
Premises ready for occupancy; (b) the holding over or retention of possession of
any tenant or occupant; (c) the Construction Improvements have not been
substantially completed due to delays by Landlord; or (d) for any other reason
beyond the control of Landlord, Landlord shall not be subject to any liability
for the failure to tender possession on said date. Under such circumstances the
Base Annual Rent and Additional Rent reserved and covenanted to be paid herein
shall not commence until possession of the Demised Premises is tendered to
Tenant. No such failure to tender possession on the Commencement Date set forth
in Section 1.2 shall in any other respect affect the validity of this Lease or
the obligations of Tenant hereunder, nor shall same be construed to extend the
termination date of this Lease set forth in Section 1.2. In the event the actual
Commencement Date does not occur within one (1) year of the date this Lease is
fully executed and delivered by Landlord and Tenant, then Landlord, without
further liability to Tenant, shall have the right to terminate this Lease upon
thirty (30) days prior written notice to Tenant. If permission is given to
Tenant to enter into possession of the Demised Premises prior to the date
specified as the Commencement Date, Tenant covenants and agrees that such
occupancy shall be deemed to be subject to all of the terms, covenants,
conditions and provisions of this Lease, and that Tenant shall be responsible
for payment of Base Annual Rent, in advance, at the rate of 1/30th of the base
monthly rent set forth in Section 1.3 for each day of such occupancy prior to
the Commencement Date, and Additional Rent set forth in Section 1.5 shall begin
to accrue on such date of possession.

   3.3  Permits. Tenant shall be responsible for obtaining at its sole cost and
expense the construction and occupancy permits for the Demised Premises. Tenant
shall be responsible for obtaining any other permits or licenses necessary for
its lawful occupancy of the Demised Premises. Tenant shall provide Landlord with
a copy of all such permits and licenses.

   3.4  Demised Premises. Landlord shall have the right to change the location
and configuration of the Demised Premises at any time, subject to the following
terms and conditions: (a) subsequent to the Commencement Date, Landlord shall
provide Tenant not less than thirty (30) days advance written notice of the date
Tenant must vacate the Demised Premises; (b) Landlord shall provide Tenant with
substitute space of similar nature and size elsewhere in the Building or in the
Complex (the "Substitute Premises"); and (c) Landlord shall at Landlord's
expense remove Tenant's Property from the Demised Premises and reinstall them in
the Substitute Premises, and redecorate the Substitute Premises in a manner
substantially similar to the manner in which the Demised Premises were
decorated. Landlord shall use reasonable efforts to minimize the disruption to
Tenant's business, but in no event shall Landlord be


                                      7
<PAGE>   14


liable for any loss of business or other damages to or expenses of Tenant,
except for any physical damage to Tenant's Property incurred during the move.
Within ten (10) days after Landlord submits an amendment of this Lease or a
replacement lease indicating the location and configuration of the Substitute
Premises, Tenant shall execute such amendment or lease, as applicable, and
deliver it to Landlord, failing which Tenant hereby irrevocably appoints
Landlord as its special attorney-in-fact to execute such amendment or lease, as
applicable, the foregoing power of attorney being deemed to be coupled with an
interest.

4.      SUBLETTING AND ASSIGNMENT

   4.1  Consent. Without the prior written Consent of Landlord, not to be
unreasonably withheld or delayed in accordance with Section 4.5, Tenant will not
sublet the Demised Premises or any part thereof or transfer possession or
occupancy thereof to any person. firm or entity, or transfer or assign this
Lease, and no subletting or assignment hereof shall be effected by operation of
law or in any other manner, such as the transfer of all or substantially all of
Tenant's assets or voting control of Tenant's stock, partnership interest or
other equity, without such prior written consent of Landlord. If Tenant is a
partnership, then any sale, conveyance, or other transfer of, or the grant of a
security interest in, any partnership interest, or any dissolution of Tenant, or
any act which will result in a potential future change in control, or a
withdrawal or change, whether voluntary, involuntary or by operation of law, of
a partner or partners owning a controlling interest in Tenant, shall be deemed a
voluntary assignment of this Lease. If Tenant is a corporation, then any sale,
conveyance, or other transfer of, or grant of a security interest in any
controlling shares of stock, dissolution, merger, consolidation or other
reorganization of Tenant, or any sale or transfer of a controlling interest of
its capital stock, or any act which will result in a potential future change in
control, or a withdrawal or change, whether voluntary, involuntary or by
operation of law, of a shareholder or shareholders owning a controlling interest
in Tenant, shall be deemed a voluntary assignment of this Lease. All permitted
sublettings and assignments of the Demised Premises and this Lease shall be
subject to the provisions of this Lease, including but not limited to Section
4.3. No assignment shall be made except for the entire Demised Premises and
Tenant further agrees that any permitted assignment of this Lease or subletting
of the Demised Premises may be conditioned upon payment by Tenant of
consideration and the delivery of such additional guarantees, collateral and/or
other security as determined by Landlord. Any subletting or assignment consented
to by Landlord, to be effective, shall be evidenced in writing in a form
acceptable to Landlord. Consent by Landlord to any assignment or subletting by
Tenant shall not operate as a waiver of the necessity for obtaining Landlord's
consent in writing to any subsequent assignment or subletting. The collection or
acceptance of rent from any such assignee, subtenant or other occupant shall not
constitute a waiver of or release of Tenant from any covenant or obligation
contained in this Lease, nor shall such acceptance of rent be deemed to create
any right to the Demised Premises in such assignee, subtenant or other occupant,
nor any legal or other relationship between the Landlord and any such assignee,
subtenant or other occupant. Landlord's acceptance of any name for listing on
the Building directory shall not be deemed, nor will it substitute for,
Landlord's consent as required by this Lease, to each sublease, assignment and
any other occupancy of the Demised Premises. In the event that Tenant defaults
under this Lease in the payment of Base Annual Rent or Additional Rent, Tenant
hereby assigns to Landlord the rent and other sums due from any subtenant,
assignee or other occupant and hereby authorizes each such subtenant, assignee
and other occupant to pay said rent and other sums directly to Landlord upon
demand. Any transfer of this Lease or the Demised Premises, or any transfer of
any interest in Tenant restricted pursuant to this Section 4.1, without the
prior written consent of Landlord pursuant to this Section 4.1 shall be void. By
taking a transfer of this Lease by assignment, transfer of interest in Tenant,
or by any other manner described in this Section 4.1, or otherwise with
Landlord's consent to the transfer, the transferee shall be bound by all
provisions of this Lease, which shall be binding upon the transferee as if the
transferee had signed this Lease in lieu of the original Tenant named herein.

   4.2  Recapture of Premises. In the event Tenant desires to sublet the Demised
Premises or assign this Lease or effect the transfer of any interest in this
Lease or in Tenant restricted pursuant to Section 4.1, Tenant shall give to
Landlord written notice of Tenant's intended subtenant, assignee or transferee
in order to secure Landlord's written consent in accordance with Section 4.1.
Within ninety (90) days of receipt of said notice, Landlord shall have the
right, at its option: (i) to terminate this Lease by giving Tenant not less than
thirty (30) days notice if Tenant's notice states the Tenant's desire to assign
this Lease or sublet more than fifty percent (50%) of the Demised Premises or
effect a restricted transfer of an interest in this Lease or in Tenant; or (ii)
if Tenant's notice states the Tenant's desire to sublet a portion of the Demised
Premises, to terminate this Lease and simultaneously to enter into a new lease
with Tenant for that portion of the Demised Premises Tenant may desire to retain
upon the same terms, covenants and conditions as then set forth in this Lease,
prorated based upon the space retained by Tenant. If Landlord exercises its
right to terminate this Lease pursuant to clauses (i) or (ii) above, Tenant
agrees that Landlord shall have access to all or any portion of the Demised
Premises sixty (60) days prior to the effective termination date for remodeling
or redecorating purposes. Tenant shall promptly execute such lease amendments
and other documents as Landlord may require to effectuate the terms and intent
of this Section 4.2.

   4.3  Excess Rent and Other Consideration. Any rent and other consideration
accruing to Tenant as the result of any sublease or any assignment of this
Lease, which is in excess of the pro rata share of Base Annual Rent and
Additional Rent then being paid by Tenant for all or a portion of the Demised
Premises being sublet or assigned, shall be paid by Tenant to Landlord monthly
as Additional Rent. Any consideration accruing to Tenant as the result of any
transfer of interest in Tenant restricted pursuant to Section 4.1, which is paid
or deemed paid in regard to the value of this Lease and which is in excess of
the pro rata share of the Base Annual Rent and Additional Rent which would have
been paid by Tenant during the Lease Term for such space, shall be paid by
Tenant to Landlord promptly as Additional Rent.

   4.4  Tenant Liability. In the event of any subletting of the Demised Premises
or assignment of this Lease by Tenant or transfer of an interest in this Lease
or in Tenant, Tenant shall remain liable to Landlord for payment of the Base
Annual Rent and Additional Rent stipulated herein and all other covenants and
conditions contained herein. No subletting of the Demised Premises or assignment
of this Lease or transfer of an interest in this Lease or in Tenant shall
operate to release, discharge or otherwise affect the liability of any
guarantors, co-signers or other parties liable to Landlord pursuant to the terms
of any guaranty or otherwise for the obligations of Tenant under this Lease.

   4.5  Reasonable Standards of Consent. Tenant acknowledges that Landlord, in
considering whether to grant or withhold consent required of Landlord pursuant
to this Section 4, shall be entitled to apply any or all of the following
criteria:

        (a)     The financial strength of proposed subtenant/assignee/transferee
must be acceptable to Landlord in Landlord's reasonable discretion based on
adequate current and historical financial information given by Tenant. Landlord
shall be entitled to receive, and Tenant shall deliver or cause others to
deliver, such guarantees, collateral and other security as Landlord shall
request in conjunction with any prospective sublease, assignment or other
transfer. Failure to provide such financial information, guarantees, collateral
and other security shall be grounds for Landlord to withhold or deny consent;


                                       8
<PAGE>   15


        (b)     The proposed subtenant/assignee/transferee must have a good
reputation in the business community and must be creditworthy;

        (c)     Use of the Demised Premises by the proposed
subtenant/assignee/transferee must be identical to the use permitted by this
Lease;

        (d)     Use of the Demised Premises by the proposed
subtenant/assignee/transferee shall not violate or create any potential
violation of any laws and must be in keeping with the character of the Building
and the Complex;

        (e)     Use of the Demised Premises by the proposed
subtenant/assignee/transferee shall not violate, or cause Landlord to violate,
any other leases, agreements or mortgages affecting (i) the Demised Premises,
the Building, the Complex or the land related to such improvements, or (ii) the
Landlord, Landlord's Agent or other tenants, whether such leases, agreements or
mortgages were entered into prior or subsequent to this Lease;

        (f)     The proposed use shall be compatible with all other uses within
the Building or Complex and the proposed use or user shall not cause a
diminution in the reputation of the Building, the Complex, Landlord, Landlord's
Agent or other tenants;

        (g)     The proposed subtenant/assignee/transferee shall have no right
to further sublet the subleased premises, nor to further assign this Lease, nor
to further transfer any interest in such proposed subtenant/assignee/transferee;

        (h)     In the event Tenant is in default, consent may be withheld
irrespective of whether these other criteria are met by the proposed
subtenant/assignee/transferee.

   4.6  Other Transfers. Notwithstanding anything herein to the contrary, Tenant
shall not pledge, assign, transfer, encumber or otherwise convey its interest in
the Demised Premises conditionally or as security for any obligations of Tenant
to any third party, or otherwise. Any such transfer in violation of this
provision shall be void.

   4.7  Rights on Default. In the event Tenant defaults under this Lease, in
addition to the rights and remedies of Landlord outlined in Section 12,
Landlord, at its option, may elect to recognize any sublease between Tenant and
any subtenant, or any agreement by which Tenant has granted any leasehold estate
or interest in the Demised Premises, as a direct lease or agreement between
Landlord and such subtenant or other grantee, upon written notice to Tenant and
such subtenant or other grantee, without releasing or affecting the liability of
Tenant to Landlord under this Lease, and Tenant shall be deemed to have assigned
its interest in such sublease or other agreement to Landlord (without the need
for executing any further documentation evidencing same) and such subtenant or
other grantee shall attorn to and recognize the rights of Landlord under such
sublease or other agreement, as the case may be. Notwithstanding Tenant's
consent or acquiescence in the termination of this Lease and/or Tenant's
voluntary surrender of the Demised Premises (or any portion thereof), Landlord
may consider any sublease or other agreement transferring a leasehold estate or
interest in the Demised Premises, and/or any right to use or possess the Demised
Premises (or any portion thereof) by any subtenant or other grantee, terminated
as of the date Landlord terminates this Lease and/or Tenant's right to
possession of the Demised Premises, it being the intention of the parties that
any leasehold estate or other interest in the Demised Premises shall be subject
to the terms and conditions of this Lease, including all rights and remedies of
Landlord outlined herein, notwithstanding anything to the contrary contained in
such sublease or other agreement.

5.      SERVICES AND UTILITIES

   5.1  Building Standard Services and Utilities. Subject to the limitations set
forth in Section 5.3 below, Landlord shall furnish sufficient electric current
for lighting and office equipment such as typewriters, calculators, small
copiers, desktop personal computers and word processors and similar items.
Landlord shall also furnish water for lavatory and drinking purposes, lavatory
supplies, fluorescent tube replacements, automatically operated elevator service
and nightly cleaning service in accordance with Landlord's prevailing practices
(as set forth in Exhibit D attached hereto), as they may be modified from time
to time, except that Landlord shall not be responsible for cleaning Tenant's
kitchens, private bathrooms, rugs, carpeting (except vacuuming) and drapes.
Landlord shall have no liability for and expressly disclaims any responsibility
for the engineering, design, installation, provision of or maintenance of
Tenant's telecommunications and data transmission systems and the inside wire
associated therewith. Landlord further agrees to furnish heating and cooling
during the appropriate seasons of the year, between the hours and on the days
set forth in Section 1.7 (exclusive of legal public holidays as defined in
section 6103(a) and (c) of Title 5 of the United States Code, as it may
hereafter be amended, with holidays falling on Saturday observed on the
preceding Friday and holidays falling on Sunday observed on the following
Monday). All of the aforesaid services shall be provided without cost to Tenant
except as such expenses may be included in calculating Additional Rent pursuant
to the provisions of Sections 2.2 and 2.3. Landlord shall not be liable for
failure to furnish, or for suspension or delay in furnishing, any of such
services if such failure, suspension or delay is caused by breakdown,
maintenance or repair work, strike, riot, civil commotion, governmental
regulations, emergency periods due to weather or any other cause or reason
whatever beyond the reasonable control of Landlord. Failure, suspension, delay
or interruption of services shall not result in any abatement of Base Annual
Rent or Additional Rent, be deemed an eviction or breach of this Lease
(including any express or implied covenant of quiet enjoyment), or relieve
Tenant of performance of Tenant's obligations under this Lease.

   5.2  Overtime Services. Should Tenant require heating and cooling services
beyond the hours and/or days stipulated in Section 1.7, upon receipt of at least
48 hours prior written notice from Tenant, Landlord will furnish such additional
service at the then-prevailing hourly rates for both utility services and
personnel as established by Landlord from time to time; provided, further, that
there will be a minimum charge of four (4) hours each time overtime services are
required.

   5.3  Excessive Usage.

        (a) Equipment Restrictions. Tenant will not install or operate in the
Demised Premises any heavy duty electrical equipment or machinery or any other
equipment which consumes excess gas (where applicable), excess water, excess
sewer services or excess electricity as defined in Section 5.3(b) below, without
first obtaining prior written consent of Landlord. Landlord may, among other
things, require as a condition to its consent for the installation of such
equipment or machinery that Tenant pay as Additional Rent the costs for excess
consumption of such utilities that may be occasioned by the operation of said
equipment or machinery. Landlord may make periodic inspections of the Demised
Premises at reasonable times to determine that Tenant's equipment and machinery
comply with the provisions of this Section and Section 5.4.


                                       9
<PAGE>   16

                (b) Excess E1ectrical Usage. The consumption of electricity,
including lighting, in excess of five (5) watts per square foot for any portion
of the Demised Premises shall be deemed excessive. Additionally, any individual
piece of electrically operated machinery or equipment having a name plate rating
in excess of two (2) kilowatts shall also be deemed as requiring excess electric
current.

                (c) Additional Utility Costs. Landlord shall have the right to
either require that one or more separate meters be installed to record the
consumption or use of electricity or other utilities, or cause a reputable
independent engineer to survey and determine the quantity of such utilities
consumed by such excessive use. The cost of any such survey and meters and of
installalion, maintenance and repair thereof shall be paid for by Tenant. Tenant
agrees to pay Landlord (or the utility company, if direct service is provided by
the utility company), promptly upon demand therefor, for all such consumption
and demand as shown by said meters, or a flat monthly charge determined by the
survey, as applicable, at the rates charged for such service by the local public
utility company. If Tenant's cost of such utilities based on meter readings is
to be paid to Landlord, Tenant shall pay a service charge related thereto in an
amount Landlord shall reasonably determine.

        5.4     EXCESSIVE HEAT GENERATION. Landlord shall not be liable for its
failure to maintain comfortable atmospheric conditions in all or any portion of
the Demised Premises due to heat generated by over-occupancy of the Demised
Premises or by any equipment, machinery or additional lighting installed by
Tenant (with or without Landlord's consent) that exceeds design capabilities for
the Building. Over-occupancy shall mean any occupancy of the Demised Premises in
excess of the planned occupancy disclosed by Tenant to Landlord pursuant to
Section 3.1 . If Tenant desires additional cooling to offset excessive heat
generated by such over-occupancy, equipment, machinery or additional lighting,
Tenant shall pay for auxiliary cooling equipment and the operating,
maintenance, repair and replacement costs of such equipment, including without
limitation electricity, gas, oil and water. If Tenant does not desire such
auxiliary cooling equipment, Tenant shall pay for excess electrical consumption
by the existing cooling system.

        5.5     BUILDING SECURITY. Any security system or other security
measures (collectively, the "Security System") that Landlord may undertake for
protection of the Demised Premises, the Building and/or Complex (including any
parking garages or areas) are for the protection of the physical structures only
and shall not be relied upon by Tenant, its agents, employees or invitees to
protect Tenant, Tenant's Property and Leasehold Improvements or Tenant's
employees, invitees or their property. Tenant shall not do anything to
circumvent or allow others to circumvent any Security System. Landlord shall not
be liable for any failure of any Security System to operate or for any breach or
circumvention of the Security System by others, and Landlord makes no
representations or warranties concerning the installation, performance and
monitoring of any Security System, or that it will detect or avert the
occurrences which any such Security System is intended or expected to detect or
avert.

        5.6     ROOF AND AUXILIARY SPACES. Tenant shall not use the roof, roof
utility closets or other auxiliary spaces in the Building for antennas,
condenser coolers, telecommunications and/or data transmission equipment or any
other type of equipment or for any other purpose without the prior written
consent of Landlord, which consent may be conditioned upon the terms of a
separate written agreement and the payment by Tenant of separate consideration
for the use of such space.

        5.7     TRASH REMOVAL. Tenant covenants and agrees, at its sole cost and
expense, to comply with all present and future laws, orders and regulations of
the federal, state, county, municipal and local governments, departments,
commissions, agencies and boards regarding the collection, sorting, separation
and recycling of trash. Upon request by Landlord, Tenant shall sort and separate
its trash into such categories as are provided by law. Each separately sorted
category of trash shall be placed in separate receptacles as directed by
Landlord. Landlord reserves the right to refuse to collect or accept from Tenant
any trash that is not separated and sorted as required by law and directed by
Landlord, and to require Tenant to arrange for such collection at Tenant's sole
cost and expense, utilizing a contractor satisfactory to Landlord. Tenant shall
pay all costs, expenses, fines, penalties and damages that may be imposed on
Landlord or Tenant by reason of Tenant's failure to comply with the provisions
of this Section, and Tenant, at Tenant's sole cost and expense, shall indemnify,
defend and hold Landlord harmless from and against any actions, claims and suits
(including legal fees and expenses) arising from such noncompliance, utilizing
counsel reasonably satisfactory to Landlord.

6.      USE AND UPKEEP OF PREMISES

        6.1     USE. Tenant shall use and occupy the Demised Premises only for
the purposes specified in Section 1.8 and for no other purpose whatsoever, and
shall comply, and cause its employees, agents, contractors, invitees and other
users of the Demised Premises to comply, with all applicable federal, state and
local laws, statutes, ordinances and regulations, including, but not limited to,
the ADA, zoning regulations, and smoking regulations. Any variation or deviation
from the specific use expressly set forth in Section 1.8 shall be deemed a
default of this Lease. Tenant shall pay before delinquency any business, rent
and other tax and fee that is now or hereafter assessed or imposed upon Tenant's
use or occupancy of the Demised Premises, the conduct of Tenant's business in
the Demised Premises or Tenant's Property. If any such tax or fee is enacted or
altered so that such tax or fee is imposed upon Landlord so that Landlord is
responsible for collection or payment thereof, then Tenant shall promptly pay
the amount of such tax or fee directly to the taxing authority, or if previously
paid by Landlord, to Landlord upon demand.

        6.2     ILLEGAL AND PROHIBITED USES. Tenant will not use or permit the
Demised Premises or any part thereof to be used for any disorderly, unlawful or
extra hazardous purpose and will not manufacture anything therein. Tenant will
not use or permit the Demised Premises to be used for any purposes that
interfere with the use and enjoyment by other tenants of the Building or Complex
or, in Landlord's opinion, impair the reputation or character of the Building,
Complex, Landlord or Landlord's Agent. Tenant shall immediately refrain from and
discontinue such use after receipt of written notice from Landlord.

        6.3     INSURANCE RATING. Tenant will not do or permit anything to be
done in the Demised Premises, the Building or the Complex or bring or keep
anything therein which shall in any way increase the rate of fire or other
insurance on said Building or the Complex, or on the property kept therein, or
conflict (or permit any condition to exist which would conflict) with applicable
fire laws or regulations, or with any insurance policy upon said Building or
Complex or any part thereof, or with any statute, rules or regulations enacted
or established by any appropriate governmental authority. Tenant shall be
responsible for any increase in insurance costs with respect to the Building or
Complex if the increases were caused by its actions or failure to act.

                                       10
<PAGE>   17

        6.4     ALTERATIONS

                (a) Approval Required. Tenant shall not make any alterations,
installations, changes, replacements, repairs, additions or improvements in or
to (or which interfere with) the structural elements of the Building or the
Demised Premises, or the Systems (hereinafter defined), without the prior
written consent of Landlord, which consent may be granted or withheld in
Landlord's sole and absolute discretion. Tenant shall not make any
non-structural, non-System or cosmetic alterations, changes, replacements,
repairs, additions or improvements in or to the Demised Premises or any part
thereof, without the prior written consent of Landlord, which consent shall not
be unreasonably withheld. All Tenant plans and specifications shall be submitted
to Landlord for prior approval. All Tenant engineering plans and specifications
shall be prepared at Tenant's expense by Landlord's designated engineer.
Landlord may, among other things, condition its consent upon Tenant's agreement
that any construction up-gradings required by any governmental authority as a
result of Tenant's work, either in the Demised Premises or in any other part of
the Building or Complex, will be paid for by Tenant in advance. Tenant shall not
install any equipment of any kind or nature whatsoever which will or may
necessitate any changes, replacements or additions to the water system, plumbing
system, heating system, ventilating system, air-conditioning system, supply,
return or control systems, Landlord's data system(s), or the electrical system
of the Demised Premises or the Building (collectively, the "Systems"), nor
install or use any air-conditioning unit, engine, boiler, generator, machinery,
heating unit, stove, water cooler, ventilator, radiator or any other similar
apparatus, nor modify or interfere with any of the Systems, without the prior
written consent of the Landlord, which consent may be granted or withheld in the
Landlord's sole and absolute discretion. Any auxiliary air-conditioning
equipment which Tenant may desire to install in the Demised Premises shall be
connected to the Building's commercial condenser water system, if available, and
Tenant shall pay to Landlord such reasonable charges as established by Landlord
from time to time for the use of the Building's commercial condenser water
system. Tenant shall not modify or interfere with the Systems without the prior
written consent of Landlord, and then only as Landlord may direct. Landlord may
condition its consent upon Tenant's payment of all costs to make such changes,
replacements or modifications. Tenant shall not design, configure, install, use
or arrange for the design, configuration, installation or use of its
telecommunications and data transmission systems or inside wire associated
therewith in any manner that interferes with the existing telecommunications
and/or data transmission systems or inside wire associated therewith of Landlord
or other tenants in the Building. Landlord's consent to any work by Tenant or
approval of Tenant's plans or specifications shall not be deemed a certification
that such work complies with applicable building codes, laws or regulations, nor
shall it impose any liability whatsoever upon Landlord.

                (b) Alteration Requirements. All of Tenant's approved work shall
be done in accordance with Landlord's Supplemental Rules and Regulations for
Contractors (as promulgated and amended by Landlord from time to time) and shall
be done by duly qualified, licensed and bonded contractors in accordance with
all applicable laws, codes, ordinances, rules and regulations, and Tenant shall
obtain (or give) at its cost any required permits, licenses, registrations,
notices, or inspections for performance of its work. Prior to the commencement
of such work Tenant must either deposit with Landlord evidence of the existence
of a bond deemed sufficient by Landlord against construction liens, or obtain an
executed waiver of lien from each contractor or vendor that will perform or
furnish to Tenant work, labor, services or materials for any alterations,
installations, replacements, additions or improvements in or to the Demised
Premises. Notwithstanding the aforesaid, if any mechanic's or materialman's lien
shall at any time, whether before, during or after the Lease Term, be filed
against any part of the Building or other property of Landlord by reason of
work, labor, services or materials performed for or furnished to or on behalf of
Tenant, Tenant shall forthwith cause the lien to be released of record by being
discharged or bonded off to Landlord's satisfaction within five (5) days after
being notified of the filing thereof. If Tenant shall fail to cause such lien to
be released of record within said five (5) day period, then, in addition to any
other right or remedy of Landlord, Landlord may bond off or discharge the lien
by paying the amount claimed to be due. Any amount paid by Landlord, whether as
bond premium or payment of the lien amount, and all costs and expenses,
including reasonable attorneys' fees incurred by Landlord in procuring the same
and its release from the appropriate land records, shall be due from Tenant to
Landlord as Additional Rent, and shall be payable on the first day of the next
following month, or if the Lease Term has expired, upon demand.

                (c) Removal of Leasehold Improvements and Tenant's Property. All
Leasehold Improvements within the Demised Premises shall, subject to Landlord's
right to require Tenant to remove all or any portion of the Leasehold
Improvements and restore the Demised Premises to its condition as of the date
this Lease is fully executed and delivered by Landlord and Tenant, remain at the
expiration or earlier termination of the Lease Term without disturbance,
molestation or injury. Should Landlord elect that Leasehold Improvements be
removed upon the expiration or earlier termination of the Lease Term, and/or
should Tenant fail to remove all or any portion of Tenant's Property in
accordance with the provisions of this Lease, Tenant hereby agrees that Landlord
shall have the right to cause all or any portion of the Leasehold Improvements
and/or Tenant's Property to be removed at Tenant's sole cost and expense. Tenant
hereby agrees to reimburse Landlord for the cost of such removal together with
the cost of repairing any damage resulting therefrom, and the cost of restoring
the Demised Premises to its condition as of the date this Lease is fully
executed and delivered by Landlord and Tenant. Approximately sixty (60) days
prior to Tenant's scheduled vacation of the Demised Premises, Landlord and
Tenant shall meet to review what items shall be removed and what items shall
remain as Landlord may determine. Landlord shall provide its estimate to Tenant
of the costs of such removal and the costs of any repairs to or restoration of
the Demised Premises as herein provided, and Tenant shall promptly deposit with
Landlord a sum equal to such estimated costs. In the event Tenant fails to
remove the Leasehold Improvements designated by Landlord for removal prior to
the expiration of the Lease Term and/or fails to remove Tenant's Property as
aforesaid and/or fails to make such repairs and/or restoration as aforesaid,
Landlord shall cause the removal, repair and/or restoration to be performed at
Tenant's sole expense, which expense shall not be limited by the amount of the
deposit referred to herein. Tenant shall provide for the transfer or disposal of
all items removed, failing which Landlord is hereby authorized to dispose of
same in any manner deemed appropriate, including, but not limited to, disposal
into the trash, without liability to Tenant, and at Tenant's sole cost and
expense, and Tenant shall indemnify, defend and hold harmless Landlord,
Landlord's Agent and their respective employees and agents from and against all
claims, damages, costs and expenses, including reasonable attorneys' fees,
arising from or in connection with the disposal of all or any items removed by
Landlord hereunder. In the event, for whatever reason, the parties do not meet
to review which items shall be removed and which items shall remain, and/or the
Tenant, for whatever reason, fails to deposit with the Landlord the deposit
hereinabove stated, then the Landlord is hereby authorized to proceed, as it
deems appropriate, with such removal and disposition of property, and repair
and/or restoration, without liability to Tenant, and at Tenant's sole cost and
expense.

                (d) Compliance with Laws. In the event that during the Lease
Term either Landlord or Tenant shall be required by the order or decree of any
court, or any other governmental authority, or by law, code or ordinance
(including but not limited to the ADA), to repair, alter, remove, reconstruct,
or improve any part of the Demised Premises or of the Building, then Tenant
agrees, at its sole cost and expense, to comply with such requirements imposed
on Demised Premises or Tenant and shall perform, at its expense, or Tenant shall
permit Landlord to perform, at Tenant's expense, such repairs, alterations,
removals, reconstructions, or improvements. Within

                                       11
<PAGE>   18

ten (10) days after receipt, Tenant shall advise Landlord in writing, and
provide the Landlord with copies of (as applicable), (i) any notices alleging
violation of any law, code or ordinance (including the ADA) relating to any
portion of the Demised Premises or the Building, (ii) any claims made or
threatened in writing regarding noncompliance with any law, code or ordinance
and relating to any portion of the Building or of the Demised Premises, or (iii)
any governmental or regulatory actions or investigations instituted or
threatened regarding noncompliance with any law, code or ordinance and relating
to any portion of the Building or the Demised Premises. No such order or decree
or the compliance required therewith shall have any effect whatsoever on the
obligations or covenants of Tenant herein contained. Tenant hereby waives all
claims for damages or abatement of Base Annual Rent and Additional Rent because
of such repairing, alteration, removal, reconstruction, or improvement.

        6.5     MAINTENANCE BY LANDLORD.

                (a) Landlord Repairs and Maintenance. Except to the extent that
Tenant is required to maintain and repair pursuant to Sections 5.4, 6.4, 6.7,
6.8, 6.10, 6.11, 9 and 21, Landlord shall maintain and repair all public or
common areas located within the Building, including external landscaping,
walkways and parking areas, and, except to the above extent, Landlord shall make
repairs to structural roofs, walls, standard heating, air conditioning, plumbing
and electrical systems and equipment. Except as otherwise expressly provided in
this Lease, such maintenance shall be provided without cost to Tenant, except
that (i) such expenses may be included in calculating the Additional Rent
pursuant to the provisions of Sections 2.2 and 2,3; and (ii) if such expenses
are incurred by Landlord in making repairs attributable to acts or omissions
of Tenant or Tenant's employees, agents, contractors or invitees, then Tenant
shall reimburse Landlord for all such expenses within ten (10) days after
Landlord submits a bill for such costs to Tenant. Tenant hereby waives all
claims for damages or abatement of Base Annual Rent and Additional Rent because
of such repairing, alteration, removal, reconstruction, or improvement.

                (b) Use of Demised Premises by Landlord. Landlord reserves the
right to erect, use, maintain, repair and replace all pipes, ducts, conduits,
wiring, fluids, gases, components, and similar materials and structures in and
through the Demised Premises, including any changes, additions or replacements
as Landlord may from time to time make thereto. Landlord may install any and all
materials, equipment, pipes, ducts, conduits, wires, and related fluids, gases,
components and mechanical equipment serving other portions, tenants and
occupants of the Building, in, through, under or above the Demised Premises that
Landlord deems desirable and shall have the right to locate, both vertically and
horizontally, utility lines, wiring, air ducts, flues, duct shafts, drains,
sprinkler mains and valves, and such other facilities within the Demised
Premises as may be deemed necessary by engineering design and/or code and/or
other legal requirements and to repair, alter, replace or remove these items.
These shall be located so as to cause minimum interference with Tenant's use of
the Demised Premises and shall, if possible, be located above Tenant's suspended
ceiling, if any, or as close to the concrete slab as possible, below the floor,
along column lines or in storage areas. Landlord shall have the right to remove
or abate any hazardous materials located in the Demised Premises and Tenant
shall fully cooperate with Landlord in this regard. Landlord's right to locate
facilities within the Demised Premises shall include facilities required by
tenants or occupants in levels above or below the Demised Premises as well as on
the same level as the Demised Premises. None of the above conduct by Landlord
shall be deemed to constitute an interference with Tenant's quiet enjoyment or
an actual or constructive eviction of Tenant. Tenant shall be entitled to no
abatement of Base Annual Rent or Additional Rent whatsoever on account of such
installation, location, construction, use, entry, removal, repair, maintenance
or other conduct as aforesaid.

        6.6     SIGNS AND PUBLICATIONS. No sign, advertisement or notice shall
be inscribed, painted or affixed on any part of the outside of the Building, or
in the common areas of the Building, or inside the Demised Premises where it may
be visible from the public areas of the Building, except on the directories and
doors of offices, and then only in such size, color, method of attachment and
style as Landlord shall approve. Landlord shall have the right to prohibit any
signage or publication of Tenant on the Demised Premises which in Landlord's
opinion tends to impair the reputation or character of the Building, Complex,
Landlord or Landlord's Agent. Tenant shall refrain from and discontinue such
signage or publication upon receipt of written notice from Landlord, but in no
event later than one (1) day after receipt of such notice.

        6.7     EXCESSIVE FLOOR LOAD. Landlord shall have the right to prescribe
the weight and method of installation of safes, computer equipment, and other
heavy fixtures or equipment. Tenant will not install in the Demised Premises any
item of Tenant's Property or fixtures that will place a load upon the floor
exceeding the designed floor load capacity of the floor and the Building.
Landlord may prescribe the placement and positioning of all such objects within
the Demised Premises and/or Building, and, if necessary, such objects shall be
placed upon platforms, plates or footings of such size as Landlord shall
prescribe. All damage done to the Building or the Demised Premises by installing
or removing a safe or any other article of Tenant's Property or fixtures, or due
to its being in the Demised Premises, shall be repaired at the expense of
Tenant.

        6.8     MOVING AND DELIVERIES.

                (a) Prohibitions/Notices. Moving in or out of the Building is
prohibited on days and hours specified in Section 1.7. Tenant shall only use
freight elevators and loading areas, if provided in the Building, for all moving
and deliveries. Tenant shall provide Landlord with forty-eight (48) hours
advance written notice of any move and obtain Landlord's approval therefor in
order to facilitate scheduling use of freight elevators and loading areas.

                (b) Coordination with Landlord. No freight, furniture or other
bulky matter of any description shall be received into the Building or carried
in the elevators, except as authorized by Landlord. All moving of furniture,
material and equipment shall be under the direct control and supervision of
Landlord, who shall, however, not be responsible for any damage to or charges
for moving same. Deliveries from lobby and freight areas requiring use of hand
carts shall be restricted to freight elevators. All hand carts shall be
equipped with rubber tires and side guards. Any control exercised by Landlord
hereunder shall be deemed solely for the benefit of Landlord and the Building,
and shall not be deemed to make any of Tenant's employees, agents or
contractors the agent or servant of Landlord. Tenant shall promptly remove from
the public areas in or adjacent to said Building any of Tenant's property
delivered or deposited there.

                (c) Moving Damages. Any and all damage or injury to the Demised
Premises or the Building caused by moving the property of Tenant into or out of
the Demised Premises shall be repaired at the sole cost of Tenant. In
conjunction with the foregoing, Tenant shall indemnify, defend and hold Landlord
harmless with respect to any and all damages and injuries to the Demised
Premises or the Building, and with respect to any property damage and injury to
others. Without releasing Tenant from any liability hereunder, Tenant shall
cooperate with Landlord to identify delivery contractors and movers causing
damage to the Building or Demised Premises or causing property damage or injury
to others.

                                       12

<PAGE>   19
        6.9     RULES AND REGULATIONS. Tenant shall, and shall ensure that
Tenant's agents, employees, invitees and guests, faithfully keep, observe and
perform the Building Rules and Regulations set forth in Exhibit C, attached
hereto and made a part hereof, and such amendments, modifications and additions
thereto as Landlord may promulgate from time to time, unless waived in writing
by Landlord. Any other such rules and regulations shall not substantially
interfere with the intended use of the Demised Premises, but Tenant acknowledges
that the Building Rules and Regulations, which, in Landlord's judgment, are
needed for the general well-being, operation and maintenance of the Demised
Premises, the Building and the Complex, together with their appurtenances, are
reasonable. Landlord shall have the right to specifically enforce all Building
Rules and Regulations. In addition to any other remedy provided for herein,
Landlord shall have the right to collect from Tenant a fine of $200 per incident
for each violation of said Building Rules and Regulations which is not cured
within three (3) days after written notice to Tenant. Nothing contained in this
Lease shall be construed to impose upon Landlord any duty or obligation to
enforce such Building Rules and Regulations, or the terms, conditions or
covenants contained in any other lease, as against any other tenant, and
Landlord shall not be liable to Tenant for violation of the same by any other
tenant, its employees, agents, invitees, licensees, customers, clients, family
members or guests. Further, it shall be in Landlord's reasonable judgment as to
whether Tenant is in compliance with the Building Rules and Regulations.

        6.10    TENANT MAINTENANCE AND CONDITION OF DEMISED PREMISES UPON
SURRENDER. At all times during the Lease Term, Tenant will keep the Demised
Premises and the Leasehold Improvements and Tenant's Property therein in good
order and condition, will suffer no waste or injury to the Demised Premises and
Leasehold Improvements, and will, subject to the provisions of Section 6.4(c),
at the expiration or other termination of the Lease Term, surrender and deliver
up the Demised Premises and Leasehold Improvements in like good order and
condition as they shall be at the Commencement Date, ordinary wear and tear and,
subject to the provisIons of Section 9, damage by casualty excepted.

        6.11    TENANT PROPERTY AND LEASEHOLD IMPROVEMENTS. Maintenance and
repair of Tenant's Property and any Leasehold Improvements within or related to
the Demised Premises shall be the sole responsibility of Tenant, and Landlord
shall have no obligation in connection therewith. Notwithstanding anything
herein to the contrary, and subject to the provisions of Sections 6.4 and 12.8
pertaining to removal from the Demised Premises, Tenant shall have no right to
remove from the Demised Premises any of Tenant's Property and/or Leasehold
Improvements upon and during the continuation of any default by Tenant under
this Lease.

        6.12    LANDLORD'S RIGHT TO PERFORM TENANT'S DUTIES. In the event that
repairs required to be made by Tenant pursuant to this Lease become necessary by
reason of Tenant's failure to maintain the Demised Premises, Tenant's Property
and Leasehold Improvements in good order and condition and in compliance with
all applicable laws, orders and regulations, Landlord may, but shall not be
obligated to, make repairs at Tenant's expense. Within ten (10) days after
Landlord renders a bill for the cost of said repairs, Tenant shall reimburse
Landlord.

        6.13    MEDICAL WASTE. In addition to Tenant's obligations with respect
to Hazardous Substances set forth in Section 21, Tenant shall be solely
responsible for and shall solely provide, at Tenant's sole cost and expense, for
the proper treatment, handling, removal and disposal from the Demised Premises,
the Building, the property of Landlord and the Complex, of all infectious and/or
hazardous medical waste as the same may be determined from time to time by
applicable federal, state or local laws or regulations. Landlord and Landlord's
Agent shall not be responsible for the treatment, handling, removal or disposal
of same, nor shall Landlord incur any liability to Tenant or any other parties,
or any governmental agency or division thereof, relating to same. Tenant hereby
agrees to indemnify, defend and hold Landlord and Landlord's Agent harmless with
respect to any suits, debts, expenses, liabilities, alleged violations or
non-compliance with any federal, state or local law or regulation, and any other
demands of any nature whatsoever, for any violation by Tenant of the provisions
of this Section 6.13 and for any harm to others caused or alleged to have been
caused by Tenant's medical waste.

        7.      ACCESS

        7.1     LANDLORD'S ACCESS. Landlord, Landlord's Agent, and their agents
and employees, shall have the right to enter the Demised Premises at all
reasonable times (a) to make inspections or to make such repairs and maintenance
to the Demised Premises or repairs and maintenance to other premises as Landlord
may deem necessary; (b) to exhibit the Demised Premises to prospective tenants
during the last six (6) months of the Lease Term; and (c) for any purpose
whatsoever relating to the safety, protection or preservation of the persons or
property of the other tenants, the public, the Demised Premises, the Building,
the Complex or other surrounding properties.

        7.2     RESTRICTED ACCESS. No additional locks, other devices or systems
which would restrict access to the Demised Premises shall be placed upon any
doors without the prior consent of Landlord. Landlord's consent to installation
of anti-crime warning devices or security systems shall not be unreasonably
withheld; provided Landlord shall not be required to give such consent unless
Tenant provides Landlord with a means of access to the Demised Premises for the
purposes outlined in Section 7.1 above. Unless access to the Demised Premises is
provided during the hours when cleaning service is normally rendered, Landlord
shall not be responsible for providing such service to the Demised Premises or
to those portions thereof which are inaccessible during said hours. Such
inability by Landlord to provide cleaning services to inaccessible areas shall
not entitle Tenant to any adjustment in Base Annual Rent, Additional Rent or
other sums due hereunder.

        7.3     TENANT'S ACCESS. Subject to the provisions of Sections 5.2 and
5.5, Tenant, its employees and agents shall have access to the Demised Premises,
via at least one (1) operable elevator (except in emergencies), twenty-four (24)
hours per day, 365 days per year, and, for the purpose of access to the Demised
Premises only, shall have the right in common with all other tenants, Landlord
and Landlord's agents and employees to use public corridors, elevators and
lobbies. Landlord may at any time and from time to time during the Lease Term
exclude and restrain any person from access, use or occupancy of any or all
mechanical and auxiliary spaces, roofs, public corridors, elevators and lobbies,
excepting, however, Tenant and other tenants of Landlord and bona fide invitees
of either who make use of said public facilities in accordance with the rules
and regulations established by Landlord from time to time with respect thereto.
Landlord may at any time and from time to time close all or any portion of said
public facilities to make repairs or changes, to prevent a dedication to any
person or the public, and to do and perform such other acts in and to said
public facilities as in the exercise of good business judgment Landlord shall
determine to be advisable. It shall be the duty of Tenant to keep all of said
public facilities free and clear of any obstructions created or permitted by
Tenant or resulting from Tenant's operation. In order to protect the integrity
of telephone service in the Building, Landlord may, at its option, supervise or
restrict Tenant's access to any or all equipment rooms, inside wire space and/or
conduits or the demarcation point.


                                       13


<PAGE>   20

8.      LIABILITY

        8.1     TENANT'S PROPERTY. All of Tenant's Property, the Leasehold
Improvements and the personal property of Tenant's employees, agents,
contractors, visitors and invitees in the Demised Premises or in the Building
shall be at their sole risk. Landlord, Landlord's Agent, and their respective
agents and employees shall not be liable for any damage to Tenant's Property,
the Leasehold Improvements or the property of Tenant's employees, agents,
contractors, visitors and invitees resulting from acts or omissions of any third
party, including, but not limited to, cleaning, maintenance, repair and other
contractors who do work in the Building or the Demised Premises or render
services to Landlord, Landlord's Agent, and their respective agents and
employees or other tenants. Tenant hereby expressly releases Landlord,
Landlord's Agent and their respective agents and employees from any liability
incurred or claimed by reason of damage to Tenant's Property and the Leasehold
Improvements and hereby indemnifies and holds Landlord, Landlord's Agent and
their respective agents and employees from any liability or claims by reason of
damage to the property of Tenant's employees, agents, contractors, visitors and
invitees.

        8.2     CRIMINAL ACTS OF THIRD PARTIES. Landlord, Landlord's Agent and
their respective agents and employees shall not be liable in any manner to
Tenant, its agents, employees, invitees or visitors for any injury or damage to
Tenant, Tenant's agents, employees, invitees or visitors, or their property,
caused by the criminal or intentional misconduct of third parties or of Tenant,
Tenant's employees, agents, invitees or visitors on or about the Demised
Premises, Building and/or Complex (including any parking garages and parking
areas). All claims against Landlord, Landlord's Agent and their respective
agents and employees for any such damage or injury are hereby expressly waived
by Tenant, and Tenant hereby agrees to hold harmless, defend and indemnify
Landlord, Landlord's Agent and their respective agents and employees from all
such claims and/or damages and the expenses of defending all claims made by
Tenant's employees, agents, invitees, or visitors arising out of such acts.

        8.3     PUBLIC LIABILITY. Landlord, Landlord's Agent and their
respective agents and employees assume no liability or responsibility whatsoever
with respect to the conduct and operation of the business to be conducted upon
the Demised Premises. Landlord, Landlord's Agent and their respective agents and
employees shall not be liable for any accident or injury to any person or
persons or property in or about the Demised Premises which are caused by the
conduct and operation of said business or by virtue of equipment or property of
Tenant in said Demised Premises. Tenant agrees to hold Landlord, Landlord's
Agent and their respective agents and employees harmless against all such
claims, and indemnify and defend Landlord, Landlord's Agent and their respective
agents and employees from all injuries and damages and the expenses of defending
such claims.

        8.4     CONSTRUCTION ON CONTIGUOUS PROPERTY. Landlord, Landlord's Agent
and their respective agents and employees shall not be liable for damages, nor
shall this Lease or any Base Annual Rent, Additional Rent or other sums due
hereunder be affected, for conditions arising or resulting from construction
within or around the Demised Premises or Building or Complex or on contiguous or
neighboring properties and which affect the Complex, the Building and/or the
Demised Premises.

        8.5     TENANT INSURANCE.

                (a) LIABILITY INSURANCE. During the Lease Term, Tenant at its
sole cost shall maintain public liability and property damage insurance which
includes coverage for personal injury and death, property damage, advertising
injury, completed operations and products coverage, and shall further maintain
comprehensive automobile liability insurance covering automobiles owned by
Tenant, with at least a single combined liability and property damage limit of
$1,000,000.00 insuring against all liability of Tenant and its authorized
representatives arising out of or in connection with Tenant's use or occupancy
of the Demised Premises and the business conducted therein. Landlord and
Landlord's Agent shall be named as additional insureds. All public liability
insurance and property damage insurance shall insure Landlord and Landlord's
Agent with coverage no less in scope than that necessary to meet Tenant's
obligations outlined in the indemnity provisions set forth in Sections 8.1, 8.2
and 8.3 and elsewhere in this Lease. The policy shall contain an assumed
contractual liability endorsement that refers expressly to this Lease.

                (b) FIRE AND CASUALTY INSURANCE. During the Lease Term, Tenant
at its cost shall maintain fire and extended coverage insurance on all special
or above building standard work (as defined in Exhibit B, if applicable), all
alterations and all other contents of the Demised Premises, including any
Leasehold Improvements and Tenant's Property, in an amount sufficient so that no
coinsurance penalty will be applied in case of loss.

                (c) INCREASES IN COVERAGE. Tenant shall increase its insurance
coverage as required if in the reasonable opinion of the mortgagee on the
Building, Landlord or Landlord's insurance agent such insurance coverage at that
time is not adequate.

                (d) POLICY REQUIREMENTS. All insurance required under this Lease
shall be issued by insurance companies authorized to do business in the
jurisdiction where the Building is located. Such companies shall have a
policyholder rating of at least "A" and be assigned a financial size category of
at least "Class X" as rated in the most recent edition of "Best's Key Rating
Guide" for insurance companies. If at any time during the Lease Term the rating
of any of Tenant's insurance carriers is reduced below the rating required
pursuant to the terms hereof, Tenant shall promptly replace the insurance
coverage(s) maintained with such carrier with coverage(s) from a carrier whose
rating complies with the foregoing requirements. If the Best's Key Rating Guide
is discontinued or revised without substitution of a comparable rating system,
Landlord shall reasonably determine its satisfaction with the insurance company
issuing Tenant's policies. Each policy shall contain an endorsement requiring
thirty (30) days written notice from the insurance company to Landlord before
cancellation or any change decreasing coverage, scope or amount of such policy
and an endorsement naming Landlord and Landlord's Agent as additional insureds.
Each policy, or a certified copy of the policy, and a certificate showing it is
in effect, together with evidence of payment of premiums, shall be deposited
with Landlord at the commencement of the Lease Term and thereafter upon any
policy changes or substitutions, and renewal certificates and copies of renewal
policies shall be delivered to Landlord at least thirty (30) days prior to the
expiration date of any policy.

                (e) NO LIMITATION OF LIABILITY. Notwithstanding the fact that
any liability of Tenant to Landlord may be covered by Tenant's insurance,
Tenant's liability shall in no way be limited by the amount of its insurance
recovery or the amount of insurance in force or required by any provisions of
this Lease.


                                       14

<PAGE>   21

                (f) WAIVER OF SUBROGATION. Notwithstanding anything to the
contrary contained herein, Landlord and Tenant hereby mutually waive and release
their respective rights of recovery against each other for any loss of its
property (in excess of a reasonable deductible amount) capable of being insured
against by fire and extended coverage insurance or any insurance policy
providing property damage coverage, whether carried or not. Each party shall
apply to its insurer to obtain said waiver and obtain any special endorsement,
if required by its insurer to evidence compliance with the aforementioned
waiver, and shall bear the cost therefor.

                (g) BUSINESS INTERRUPTION. Landlord, Landlord's Agent and their
respective agents and employees shall have no liability or responsibility for
any loss, cost, damage or expense arising out of or due to any interruption of
business (regardless of the cause therefor), increased or additional cost of
operation of business or other costs or expenses, whether similar or dissimilar,
which are capable of being insured against under business interruption
insurance, whether or not carried by Tenant.

        8.6     INCIDENT REPORTS. Tenant shall promptly report to Landlord's
Agent all accidents and incidents occurring on or about the Demised Premises,
the Building and/or the Complex which involve or relate to the security and
safety of persons and/or property.

9.      DAMAGE

        9.1     DAMAGES CAUSED BY TENANT. Subject to the provisions of Sections
8.5(f) and 9.2, in the event of damage to the Demised Premises or other portions
of the Building caused by the acts or omissions of Tenant, its agents,
employees, invitees or visitors, the Landlord may, but shall not be obligated
to, repair such damage at the expense of Tenant, or, at Landlord's option, such
damages shall be repaired by Tenant, at Tenant's expense, with Landlord's
approval in accordance with Section 6.4. At Landlord's option, Tenant shall
either (a) pay to Landlord the estimated cost of such repairs and/or maintenance
within ten (10) days of Tenant's receipt of Landlord's estimate, or (b) upon
completion of such repairs and/or maintenance by Landlord, pay to Landlord the
actual cost of such repairs and/or maintenance (or the difference between the
actual cost and the estimated costs previously paid by Tenant) within ten (10)
days of receipt of invoice from Landlord. Landlord's recovery shall not be
limited to the diminution in the value of the Demised Premises or leasehold
notwithstanding that such repairs and maintenance may occur prior to the
expiration of the Lease Term. All such costs shall be deemed Additional Rent.
This provision shall be construed as an additional remedy granted to Landlord
and not in limitation of any other rights and remedies which Landlord has or may
have in said circumstances.

        9.2     FIRE OR CASUALTY DAMAGE. In the event of damage or destruction
of the Demised Premises or a portion thereof by fire or any other casualty not
due to the acts or omissions of Tenant, its agents, employees, invitees or
visitors, then, except as otherwise provided in Section 9.3, this Lease shall
not be terminated, but structural damage to the Demised Premises, including
demising partitions and doors, shall be promptly and fully repaired and restored
as the case may be by Landlord at its own cost and expense. Due allowance,
however, shall be given for reasonable time required for adjustment and
settlement of insurance claims, and for such other delays as may result from
government restrictions, and controls on construction, if any, and for strikes,
national emergencies and other conditions beyond the control of Landlord.
Restoration by Landlord shall not include replacement of Tenant's Property or
that portion of the Leasehold Improvements provided by Landlord as of the
Commencement Date above the building standard items as of the Commencement Date.
If the items which Landlord provides as building standard items have changed
since the Commencement Date, then, at Landlord's election, such restoration
shall not include restoration of Leasehold Improvements in excess of those
provided by Landlord as building standard as of the date of such restoration.
Tenant shall, at its expense, repair, restore and replace Tenants Property and
all elements of the Demised Premises excluded from the scope of Landlord's duty
to restore pursuant to this Section 9.2. Tenant's restoration, replacement and
repair work shall comply with Section 6 hereof and Tenant shall maintain
adequate insurance on all such replacements, restoration and property pursuant
to Section 8.5. In the event of fire or casualty damage to the Demised Premises
caused by the fault, act or omission or neglect of Tenant, its agents,
employees, invitees or visitors, Landlord may, but shall not be obligated to,
restore all or any portion of the damage described herein (which may or may not
include the Demised Premises). It is agreed that in any of the aforesaid events,
this Lease shall continue in full force and effect.

9.3     UNTENANTABILITY.

        (a)     Restoration Requirements.

                (i)     If the condition referred to in Section 9.2 is such that
the Demised Premises are partially damaged or destroyed and provided that the
condition was not due to the acts or omissions of Tenant, its agents, employees,
invitees or visitors, then during the period that Tenant is deprived of the use
of the damaged portion of the Demised Premises, Tenant shall be required to pay
Base Annual Rent and Additional Rent covering only that part of the Demised
Premises that Tenant is able to occupy, based on the ratio between the square
foot area remaining that can be occupied and the total square foot area of the
entire Demised Premises covered by this Lease. Any unpaid or prepaid installment
of Base Annual Rent and Additional Rent for the month in which the condition
referred to in Section 9.2 occurs shall be prorated.

                (ii)    (1) If the condition referred to in Section 9.2 is such
so as to make the entire Demised Premises untenantable and provided that the
condition was not due to the acts or omissions of Tenant, its agents, employees,
invitees or visitors, then, subject to the rights set forth in Section
9.3(a)(ii)(2) below, the installment(s) of Base Annual Rent and Additional Rent
which Tenant is obligated to pay hereunder shall abate as of the date of the
occurrence until the restoration of the Demised Premises has been substantially
completed by Landlord to the extent of Landlord's obligations as described in
Section 9.2. Any unpaid or prepaid installment of Base Annual Rent and
Additional Rent for the month in which the condition referred to in Section 9.2
occurs shall be prorated.

                        (2) In the event (x) the Demised Premises are
substantially or totally destroyed by fire or other casualty so as to be
entirely untenantable, (y) a substantial portion of the Building is destroyed or
damaged to such an extent that, in the sole judgment of Landlord, the Building
cannot be operated as a functional unit or an economically viable unit, or (z)
the damage to the Demised Premises and/or the Building is due to an uninsured
risk or insurance proceeds are otherwise unavailable to cover the expenses of
restoration or repair of the damage (less any applicable deductible), then
Landlord shall have the unconditional right to cancel this Lease in its sole
discretion, in which case Base Annual Rent and Additional Rent shall be
apportioned and paid to the date of said fire or other casualty. If Landlord
elects not to cancel this Lease, then Landlord shall determine and notify Tenant
in writing, within sixty (60) days following the fire or other casualty, of the
date by which the Demised Premises can be restored by Landlord in accordance
with the provisions of Section 9.2. If the date determined by Landlord as
aforesaid for completion of restoration of the Demised Premises is more than one
hundred twenty (120) days after such fire or other casualty, then Tenant shall
have the right, to be exercised by giving written notice to Landlord within ten
(10) days following receipt of such notice from Landlord, to cancel and
terminate this Lease.

                                       15






<PAGE>   22
In the event the date by which Landlord determines it can complete restoration
of the Demised Premises as herein provided is less than 120 days following
such fire or other casualty, or Tenant fails to terminate this Lease as herein
provided following notification from Landlord that completion of restoration
will require more than 120 days, then this Lease shall remain in full force
and effect and Landlord shall commence restoration of the Demised Premises to
the extent of Landlord's obligations as described in Section 9.2. Due
allowance, however, shall be given for reasonable time required for adjustment
and settlement of insurance claims, for Landlord to reasonably be able to
determine the time necessary for completion of the restoration and for other
such delays as may result from government restrictions, and controls on
construction, if any, and for strikes, national emergencies and other
conditions beyond the control of Landlord. Any delays as a result of the
foregoing shall operate to postpone Landlord's obligation to complete
restoration of the Demised Premises by one day for each day of any such delay.
Tenant shall commence any restoration to be performed by Tenant as required in
Section 9.2 and Tenant shall reoccupy the Demised Premises when restored.

          (iii) Except as expressly provided in this Section 9.3, no
compensation, or claim, or diminution of Base Annual Rent or Additional Rent
will be allowed or paid by Landlord, by reason of inconvenience, annoyance, or
injury to business, arising from any fire or other casualty suffered by Tenant
or the necessity of repairing or restoring the Demised Premises or any portion
of the Building.

      (b) Casualty Near Expiration of Lease Term. In addition to any other right
of Landlord or Tenant to terminate this Lease pursuant to the provisions of this
Section 9, in the event the Demised Premises are damaged in whole or in part by
fire or other casualty during the last twelve (12) months of the Lease Term,
then Landlord or Tenant, upon ten (10) days prior written notice to the other
given within sixty (60) days of the date of the fire or casualty, may terminate
this Lease, in which case the Base Annual Rent and Additional Rent shall be
apportioned and paid to the date of said fire or other casualty; provided,
however, Tenant shall have no right to terminate this Lease hereunder if prior
to receipt of Tenant's notice Landlord has commenced to repair or restore the
Demised Premises.

10.   CONDEMNATION

   10.1 Landlord's Right to Award. Tenant agrees that if any of the Demised
Premises or the Building shall be taken or condemned for public or
quasi-public use or purpose by any competent authority, Tenant shall have no
claim against Landlord and shall not have any claim or right to any portion of
the amount that may be awarded as damages or paid as a result of any such
condemnation. All rights of Tenant to damages therefor, if any, are hereby
assigned by Tenant to Landlord. If (a) the whole or a substantial part of the
Demised Premises or the Building is taken or condemned or if (b) less than a
substantial portion of the Building or the Demised Premises is taken or
condemned and the remainder of either in Landlord's opinion can not be
operated as a functional unit or as an economically viable unit, the Lease
Term shall cease and terminate from the date of such governmental taking or
condemnation and Landlord shall notify Tenant of the termination of this Lease
effective as of the date of such governmental taking or condemnation. In the
event of any termination of this Lease by reason of any taking or
condemnation, Tenant shall have no claim against Landlord or Landlord's Agent
for the value of any unexpired portion of the Lease Term. If less than a
substantial part of the Demised Premises or of the Building is taken or
condemned by any governmental authority for public or quasi-public use or
purpose and the remainder of both in Landlord's opinion can be operated as a
functional unit or as an economically viable unit, the rent shall be equitably
adjusted on the date when title vests in such governmental authority and the
Lease shall otherwise continue in full force and effect. For the purposes of
this Section 10, a substantial part of the Demised Premises shall be
considered to have been taken if more than fifty percent (50%) of the Demised
Premises are unusable by Tenant.

   10.2 Tenant's Right to File Claim. Nothing in Section 10.1 shall preclude
Tenant from filing a separate claim against the condemning authority for the
value of its Leasehold Improvements not then depreciated (excluding those
Leasehold Improvements paid for by Landlord) and relocation expenses, provided
that any award to Tenant will not result in a diminution of any award to
Landlord.

11.   BANKRUPTCY

   11.1 Events of Bankruptcy. The following shall be Events of Bankruptcy
under this Lease:

       (a) Tenant's becoming insolvent, as that term is defined in Title 11 of
the United States Code, entitled Bankruptcy, 11 U.S.C. Sec. 101 et seq. (the
"Bankruptcy Code"), or under the insolvency laws of any State, District,
Commonwealth or Territory of the United States ("Insolvency Laws");

       (b) The appointment of a receiver or custodian for any or all of
Tenant's Property or assets, or the institution of a foreclosure action upon
any of Tenant's real or personal property;

       (c) The filing of a voluntary petition under the provisions of the
Bankruptcy Code or Insolvency Laws;

       (d) The filing of an involuntary petition against Tenant as the subject
debtor under the Bankruptcy Code or Insolvency Laws, which is either not
dismissed within sixty (60) days of filing, or results in the issuance of an
order for relief against the debtor, whichever is earlier; or

       (e) Tenant's making or consenting to an assignment for the benefit of
creditors or a common law composition of creditors.

   11.2 Landlord's Remedies.

       (a) Termination of Lease. Upon occurrence of an Event of Bankruptcy,
Landlord shall have the right to terminate this Lease by giving written notice
to Tenant; provided, however, that this right to terminate shall have no
effect while a case in which Tenant is the subject debtor under the Bankruptcy
Code is pending, unless Tenant or its Trustee is unable to comply with the
provisions of Sections 11.2(d) and (e) below. At all other times this Lease
shall automatically cease and terminate, and Tenant shall be immediately
obligated to quit the Demised Premises upon the giving of notice pursuant to
this Section 11.2(a). Any other notice to quit, or notice of Landlord's
intention to re-enter is hereby expressly waived. If Landlord elects to
terminate this Lease, everything contained in this Lease on the part of
Landlord to be done and performed shall cease without prejudice, subject,
however, to the rights of Landlord to recover from Tenant all Base Annual Rent
and Additional Rent and any other sums accrued up to the time of termination
or recovery of possession by Landlord, whichever is later, and any other
monetary damages sustained by Landlord.

                                      16
<PAGE>   23


       (b) Suit for Possession. Upon termination of this Lease pursuant to
Section 11.2(a), Landlord may proceed to recover possession of the Demised
Premises under and by virtue of the provisions of the laws of any applicable
jurisdiction, or by such other proceedings, including reentry and possession,
as may be applicable, or by direct order from any Court having jurisdiction
over Tenant/Debtor, including any Bankruptcy Court.

       (c) Non-Exclusve Remedies. Without regard to any action by Landlord as
authorized by Sections 11.2(a) and (b) above, Landlord may at its discretion
exercise all the additional provisions set forth below in Section 12.

       (d) Assumption or Assignment by Trustee. In the event Tenant becomes
the subject debtor in a case pending under the Bankruptcy Code, Landlord's
right to terminate this Lease pursuant to Section 11.2(a) shall be subject to
the rights of the Trustee in Bankruptcy to assume or assign this Lease. In
addition to all other objections Landlord may raise to assumption and/or
assignment, and in addition to all other requirements of any Bankruptcy Court
and the Bankruptcy Code, the Trustee shall not have the right to assume or
assign this Lease unless the Trustee (i) has timely performed all Lease
obligations of the Tenant/Debtor arising from and after the filing of any
voluntary bankruptcy petition by Tenant or, in the case of an involuntary
petition, the date of entry of the Order for Relief, (ii) promptly cures all
defaults under this Lease, (iii) promptly compensates Landlord for monetary
damages incurred as a result of such default, and (iv) provides adequate
assurance of future performance on the part of Tenant or on the part of the
assignee of Tenant or the Trustee.

       (e) Adequate Assurance of Future Performance. Landlord and Tenant
hereby agree in advance that adequate assurance of future performance, as that
term is used in Section 11.2(d) above, shall mean that all of the following
minimum criteria must be met: (i) Tenant's gross revenues in the ordinary
course of business during the thirty (30) day period immediately preceding the
initiation of the case under the Bankruptcy Code must be at least two (2)
times greater than the next installment of Base Annual Rent and Additional
Rent due under this Lease; (ii) both the average and median of Tenant's gross
revenues in the ordinary course of business during the six (6) month period
immediately preceding the initiation of the case under the Bankruptcy Code
must be at least two (2) times greater than the next six (6) installments of
Base Annual Rent and Additional Rent due under this Lease; (iii) Tenant must
pay (and continue to pay on a timely basis throughout the Lease Term) Base
Annual Rent, Additional Rent and all other sums payable by Tenant hereunder in
advance and as a condition precedent to the performance of Landlord's
obligations hereunder; (iv) the Trustee must agree that Tenant's business
shall be conducted in a first class manner, and that no liquidating sales,
auctions, or other non-first class business operations shall be conducted on
or about the Demised Premises, Building and/or Complex; (v) the Trustee must
agree that the use of the Demised Premises as stated in this Lease will remain
unchanged and that no prohibited use shall be permitted; and (vi) the Trustee
must agree that the assumption or assignment of this Lease will not violate or
affect the rights of other tenants in the Building and/or Complex.

       (f) Failure to Provide Adequate Assurance. In the event the Trustee or
Tenant is unable to (i) comply with the requirements of Section 11.2(d) above,
or (ii) meet the criteria and obligations imposed by Section 11.2(e) above,
Tenant agrees in advance that it has not met its burden to provide adequate
assurance of future performance, and this Lease may be terminated by Landlord
in accordance with Section 11.2(a) above.

   11.3 Guarantors. For purposes of this Section 11, any action or
adjudication by or on behalf of, or against, or with respect to the property
or affairs of, any guarantor or guarantors (if any) of this Lease, or any of
them, which, if taken by, against or with respect to Tenant, Tenant's Property
or affairs, would entitle Landlord to exercise any remedy specified herein,
may be treated, at Landlord's sole option and discretion, as though it were
taken by, against or with respect to the Tenant.

   11.4 Damages. In the event of cancellation and termination of this Lease
pursuant to Section 11.2 above, Landlord shall, notwithstanding any other
provisions of this Lease to the contrary, be entitled to promptly recover
damages from Tenant determined in accordance with the provisions set forth in
Section 12.2 of this Lease as provided for in the case of default by Tenant.

12.    DEFAULTS AND REMEDIES

   12.1 Default. If any one or more of the following events occur, said event
shall be deemed a material default of this Lease:

       (a) Tenant's failure to complete, within the time periods required by
this Lease, any tasks required for the preparation or approval of plans for
the construction and/or completion of the Demised Premises prior to the
Commencement Date;

       (b) Tenant's failure to accept possession of the Demised Premises when
tendered by Landlord;

       (c) Tenant's failure to pay any installment of Base Annual Rent,
Additional Rent or other sum required to be paid by Tenant when the same shall
be due and payable, all without demand unless demand is necessary under the
express terms of this Lease (in which case a material default shall be deemed
to occur if such payment is not made strictly within the time period provided
for such payment following the demand);

       (d) Tenant's failure to perform or observe any other term, covenant or
condition of this Lease;

       (e) Any event expressly designated or deemed a default elsewhere in
this Lease;

       (f) Any execution, levy, attachment or other legal process of law shall
occur upon Tenant's Property, Tenant's interest in this Lease or the Demised
Premises;

       (g) Tenant's abandonment or surrender of the Demised Premises prior to
the expiration of the Lease Term and the suspension of rent payments as the
same may become due and payable; and/or

       (h) Tenant's committing or permitting waste to occur to the Demised
Premises.

   12.2 Remedies. In each and every such event set forth in Section 12.1
above, from the date of such default and at all times thereafter, at the
option of Landlord, Tenant's right of possession shall thereupon cease and
terminate. Landlord shall be entitled to all rights and remedies now or later
allowed at law or in equity, all of which shall be cumulative to the extent
that the exercise of any one or more rights or remedies shall not be deemed to
constitute a waiver of the Landlord's right to exercise any one or more other



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<PAGE>   24


rights and remedies herein provided or provided at law or in equity. Landlord
shall be entitled to obtain possession of the Demised Premises whether or not
Landlord elects to terminate this Lease, and to re-enter the same without
demand of rent or demand of possession of the Demised Premises and may
forthwith proceed to recover possession of the Demised Premises by any lawful
means or process of law whether or not Landlord elects to terminate this
Lease, any notice to quit being hereby expressly waived by Tenant. In the
event of such re-entry by process of law or otherwise, Tenant nevertheless
agrees to remain liable for all Base Annual Rent, Additional Rent and other
sums due under this Lease, and shall pay the same as and when it accrues and
is payable hereunder. Landlord may (but shall not be obligated to) declare the
entire balance (or any portion thereof) of Base Annual Rent, Additional Rent
and all other sums payable by Tenant hereunder for the remainder of the Lease
Term to be immediately due and payable in full, which shall be recoverable
pursuant to Section 12.4 below. Tenant further agrees to remain liable for any
and all damage, deficiency, and loss of Base Annual Rent, Additional Rent and
other sums herein specified, and all other damages which Landlord may sustain
by such re-entry, including reasonable attorneys' fees and costs. If under the
provisions hereof, a seven (7) days summons or other applicable summary
process shall be served, and a compromise or settlement thereof shall be made,
such action shall not constitute a waiver of any breach of any covenant, term,
condition or agreement herein contained.

   12.3 Landlord's Rlght to Relet. Should this Lease be terminated before the
expiration of the Lease Term, by reason of Tenant's default as provided in
Sections 11 or 12, or if Tenant shall abandon the Demised Premises before the
expiration or termination of the Lease Term and without paying the rent due as
the same may become due and payable (whether or not Landlord elects to
terminate this Lease), the Demised Premises may be relet by Landlord, on
Tenant's behalf or for the account of Landlord, as Landlord so chooses, for
such rent and upon such terms as are reasonable under the circumstances. If
the full rent reserved under this Lease (and any of the costs, expenses or
damages indicated below) shall not be realized by Landlord, Tenant shall be
liable for all damages sustained by Landlord, including, without limitation,
deficiency in Base Annual Rent, Additional Rent, unamortized Landlord
Concessions (hereinafter defined), reasonable attorneys' fees, other
collection costs, brokerage fees, expenses incurred by Landlord to remove
Tenant's Property and (at Landlord's option) Leasehold Improvements, and
expenses of placing the Demised Premises in first-class rentable condition.
Landlord, in putting the Demised Premises in good order or preparing the same
for reletting may, at Landlord's option, make such alterations, repairs or
replacements in or relating to the Demised Premises as Landlord, in Landlord's
sole judgment, considers advisable and necessary for the purpose of reletting
the Demised Premises, and the making of such alterations, repairs or
replacements shall not operate or be construed to release Tenant from
liability hereunder as aforesaid. Landlord shall in no event be charged with
any obligation to mitigate its damages nor shall Landlord be liable in any way
whatsoever for failure to relet the Demised Premises, or in the event that the
Demised Premises are relet, for failure to collect the rent thereof under such
reletting. For the purpose of calculating Landlord's damages as set forth in
Section 12.4 below, if the Building has other available space at the time of
such Lease termination or Tenant's abandonment or vacating of the Demised
Premises, or anytime thereafter, the Demised Premises shall be deemed the last
space rented in the Building even though the Demised Premises may be re-rented
by Landlord prior to such other vacant space. In no event shall Tenant be
entitled to receive any excess, if any, of rent (if any) collected over the
sums payable by Tenant to Landlord hereunder.

   12.4 Recovery of Damages.

       (a) Qualification of Damages. Any damage, deficiency, loss of Base
Annual Rent, Additional Rent or other sums payable by Tenant hereunder,
unamortized Landlord Concessions as described hereinafter, and all other
damages may be recovered by Landlord, at Landlord's option, upon default by
Tenant, in separate actions, from time to time, as said damage shall have
periodically accrued, or, at Landlord's option, may be deferred until the
expiration of the Lease Term (in which event Tenant hereby agrees that the
cause of action shall not be deemed to have accrued until the date of
expiration of said Lease Term), or, at Landlord's option, in a single action
in the event Landlord shall have declared the entire balance of Base Annual
Rent, Additional Rent and other sums due under this Lease immediately due and
payable pursuant to Section 12.2. In the event Landlord shall have declared
the entire balance of Base Annual Rent, Additional Rent and other sums due
under this Lease immediately due and payable, then in lieu of the Base Annual
Rent and Additional Rent which would have been payable for the period after
the date of any judgment obtained in any action by Landlord against Tenant to
recover damages, Tenant shall pay a sum representing liquidated damages, and
not penalty, in an amount equal to the excess of (i) the sum of the Base
Annual Rent and Additional Rent provided for in this Lease for the unexpired
portion of the Lease Term after the date of judgment discounted at a rate of
three percent (3%) per annum to present value, over (ii) the rental value of
the Leased Premises, at the time of termination of this Lease, for the
unexpired portion of the Lease Term, discounted at a rate of three percent
(3%) per annum to present value. In determining the rental value of the Leased
Premises, the rent realized by any reletting accomplished or accepted by
Landlord within a reasonable time after termination of this Lease, shall be
deemed, prima facie, to be the rental value. In addition to all of the rights
of the Landlord to recover damages herein provided, Tenant shall immediately
reimburse Landlord for, and Landlord may recover, the unamortized portion of
all contributions and other concessions (hereinafter "Landlord Concessions"),
if any, provided by Landlord to Tenant as an inducement to enter into this
Lease and any amendment, modification or extension hereof and/or pursuant to
the terms of this Lease or any amendment, modification or extension hereof,
including, but not limited to, (i) any abatements or waivers of Base Annual
Rent, Additional Rent or other sums due under this Lease, (ii) costs incurred
by Landlord in making the Demised Premises ready for Tenant's occupancy,
including the cost of the Construction Improvements, any monetary contribution
by Landlord for any Leasehold Improvements and any other contributions by
Landlord with respect to any construction within or relating to the Demised
Premises, (iii) moving expenses, (iv) brokerage fees, (v) allowances for
telephone and computer systems and other office equipment and supplies, (vi)
design, architectural and engineering fees and expenses, and (vii) any other
direct or indirect expenses incurred by Landlord in conjunction with obtaining
and/or entering into this Lease and any amendment, modification and extension
hereof, and placing and/or retaining Tenant in possession of the Demised
Premises. For purposes hereof, the amount of any Landlord Concessions provided
in connection with the initial Lease Term shall be deemed to be amortized
(using a straight-line method) on a monthly basis over the initial Lease Term
(excluding any extension or renewal terms) in which Tenant is required to pay
all or any portion of any installment of Base Annual Rent under the terms of
this Lease. The amount of any Landlord Concessions provided in connection with
any amendment or modification of this Lease during the initial Lease Term
shall be deemed to be amortized (using a straight-line method) on a monthly
basis over the remaining months in the initial Lease Term (excluding any
extension or renewal terms) in which Tenant is required to pay all or any
portion of any installment of Base Annual Rent under the terms of this Lease.
The amount of any Landlord Concessions provided in connection with any renewal
or extension of the Lease Term shall be deemed to be amortized (using a
straight-line method) on a monthly basis over the months in the extension
period (excluding any subsequent extension or renewal terms) in which Tenant
is required to pay all or any portion of any installment of Base Annual Rent
under the terms of said extension or renewal of the Lease Term.




                                      18



<PAGE>   25

        (b) Non-Exclusive Rights. The provisions contained in this Section 12.4
shall be in addition to and shall not prevent the enforcement of any claim
Landlord may have against Tenant for anticipatory breach of the unexpired Lease
Term. All rights and remedies of Landlord under this Lease shall be cumulative
and shall not be exclusive of any other rights and remedies provided to
Landlord under applicable law. In the event Tenant becomes the subject debtor
in a case under the Bankruptcy Code, the provisions of this Section 12.4 may be
limited by the limitations of damage provisions of the Bankruptcy Code.

   12.5 WAIVER. If under the provisions hereof Landlord shall institute
proceedings and a compromise or settlement thereof shall be made, the same
shall not constitute a waiver of any agreement, covenant, condition, rule or
regulation herein contained nor of any of Landlord's rights hereunder. No
waiver by Landlord of any breach of any agreement, covenant, condition, rule or
regulation herein contained, on one or more occasions, shall operate as a
waiver of such agreement, covenant, condition, rule or regulation itself, or of
any subsequent breach thereof. No provision of this Lease shall be deemed to
have been waived by Landlord unless such waiver shall be in writing signed by
Landlord. Receipt and acceptance by Landlord of any Base Annual Rent,
Additional Rent or other charges, or the performance of any obligation by
Tenant hereunder, with knowledge of the breach of any agreement, covenant,
condition, rule or regulation of this Lease by Tenant shall not be deemed a
waiver of such breach. Failure of Landlord to enforce any of the rules and
regulations against Tenant or any other tenant in the Building or Complex shall
not be deemed a waiver of any such rule or regulation. No payment by Tenant or
receipt by Landlord of a lesser amount than the Base Annual Rent and Additional
Rent herein stipulated shall be binding upon Landlord, nor shall the same be
deemed to be other than on account of the stipulated Base Annual Rent and
Additional Rent. No endorsement or statement on any check, letter or other
transmittal accompanying any check or payment of Base Annual Rent, Additional
Rent or other sum due from Tenant shall be deemed a settlement of a legal
dispute or an accord and satisfaction, and Landlord may accept such check or
payment without prejudice to Landlord's right to recover the balance of such
Base Annual Rent, Additional Rent and other sums or to pursue any other remedy
provided in this Lease. Landlord's consent to, or approval of, any act by
Tenant requiring Landlord's consent or approval shall not be deemed to waive or
render unnecessary Landlord's consent to or approval of any subsequent act by
Tenant.

   12.6 ANTICIPATORY REPUDIATION.

        (a) Repudiation Prior to Commencement Date. If, prior to the
Commencement Date or the first day of any extension or renewal period set forth
in an extension or renewal option validly exercised by Tenant hereunder, Tenant
notifies Landlord of or otherwise unequivocally demonstrates an intention to
repudiate this Lease or breach any obligation of Tenant hereunder, Landlord
may, at its option, consider such anticipatory repudiation a breach and
material default of this Lease. In addition to any other remedies available to
it hereunder or at law or in equity, Landlord may retain all Base Annual Rent,
Additional Rent and other sums paid by Tenant hereunder, including any security
deposit, if any, to be applied to damages of Landlord incurred as a result of
such repudiation, including, without limitation, all damages and remedies
reserved to Landlord in this Section 12 or elsewhere in this Lease, as
applicable. It is agreed between the parties that for the purpose of
calculating Landlord's damages, if the Building has other available space at
the time of or subsequent to Tenant's breach, the Demised Premises covered by
this Lease shall be deemed the last space rented in the Building even though
the Demised Premises may be re-rented prior to such other vacant space. In the
event a default occurs prior to the Commencement Date, Tenant shall, in
addition to all other damages to which Landlord is entitled under this Lease,
pay in full for all Leasehold Improvements constructed or installed within the
Demised Premises through the date of the default, and for material ordered at
Tenant's request for the Demised Premises (whether at Tenant's request or upon
Landlord's anticipation of Tenant's needs hereunder) or for such material
restocking charges.

        (b) Repudiation of Any Obligation of Tenant during Lease Term. If
during the Lease Term Tenant notifies Landlord of or otherwise unequivocally
demonstrates an intention to repudiate this Lease or breach any obligation of
Tenant hereunder, Landlord may, at its option, consider such anticipatory
repudiation a breach and material default of this Lease. In addition to any
other remedies available to it hereunder or at law or in equity, Landlord may
retain all Base Annual Rent, Additional Rent and other sums paid by Tenant
hereunder, including any security deposit, if any, to be applied to damages of
Landlord incurred as a result of such repudiation, including, without
limitation, all damages and remedies reserved to Landlord in this Section 12 or
elsewhere in this Lease, as applicable.

   12.7 TENANT ABANDONMENT OF DEMISED PREMISES.

        (a) Abandonment. If the Demised Premises or a substantial portion
thereof shall be deserted or vacated by Tenant for thirty (30) consecutive days
or more and Tenant shall be delinquent in the payment of any Base Annual Rent,
Additional Rent or other sums due under this Lease, or in the performance of any
of Tenant's other obligations hereunder, Landlord may deem the Tenant to have
abandoned the Demised Premises, notwithstanding the fact that Tenant may have
left all or some part of Tenant's Property thereon. Landlord may consider Tenant
in default under this Lease and may pursue all remedies available to it under
this Lease or otherwise as may be available in equity or at law.

        (b) Landlord Right to Enter and to Relet. If Tenant abandons the
Demised Premises as set forth in subsection (a) above, Landlord may, at its
option, enter into the Demised Premises without being liable for any
prosecution therefor or for damages by reason thereof. In addition to any other
remedy elsewhere provided in this Section 12 or at law or in equity, Landlord,
as agent of Tenant, may relet the whole or any part of the Demised Premises for
the whole or any part of the then unexpired Lease Term. For the purposes of
such reletting, Landlord may make any alterations or modifications of the
Demised Premises considered desirable in its sole judgment.

   12.8 TENANT'S PROPERTY. Tenant shall not remove any of Tenant's Property from
the Demised Premises without the prior written consent of Landlord, other than
in the ordinary course of Tenant's business. In the event of a default under
this Lease, Tenant shall not, under any circumstances, remove Tenant's Property
from the Demised Premises and Landlord may (but shall not be obligated to) keep
Tenant's Property in place (and require Tenant to return or replace Tenant's
Property to the extent Tenant removes same in violation of the terms of this
Lease) and use, or permit another occupant of the Demised Premises, Building
and/or Complex to use, Tenant's Property during the remainder of the Lease Term
(whether or not Landlord elects to terminate this Lease for such default) at no
cost, expense or liability to Landlord or such occupant. If Tenant abandons the
Demised Premises as defined in Section 12.7(a) above or otherwise vacates the
Demised Premises or otherwise defaults under this Lease, any property that
Tenant leaves within or related to the Demised Premises shall be deemed to have
been abandoned and, without liability to Tenant, may be disposed of in the trash
or retained by Landlord as the property of Landlord or disposed of at public or
private sale, or placed at the use of another occupant in the Building or the
Complex or any subsequent occupant in the Demised Premises, as Landlord sees fit
in its sole


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<PAGE>   26

discretion, all at no cost or expense to Landlord or such other person permitted
to use all or a portion of Tenant's Property hereunder, or Landlord may store
Tenant's Property at a location selected by Landlord in its sole discretion at
Tenant's sole cost and expense. The proceeds of any public or private sale
of Tenant's Property shall be applied by Landlord against (i) the expenses of
Landlord for removal, storage or sale of the property; (ii) the arrears of Base
Annual Rent, Additional Rent or other sums then or thereafter payable under this
Lease; and (iii) any other damages to which Landlord may be entitled hereunder.
At Landlord's option, at any time during the Lease Term after default by Tenant,
Landlord may require Tenant to forthwith remove Tenant's Property from the
Demised Premises. If Tenant vacates or abandons the Demised Premises, as defined
above, Landlord may transfer any of Tenant's Property to creditors of Tenant, on
presentation of evidence of a claim valid on its face of ownership or of a
security interest in any of Tenant's Property abandoned in the Demised Premises
or the Building, and Landlord may recover any costs incurred by Landlord in
doing so, all without incurring any liability to Tenant.

   12.9 LANDLORD'S LIEN.

        (a) Right of Distress/Landlord's Lien. To secure the payment of all
Base Annual Rent, Additional Rent and all other charges and sums that may
become due to Landlord under the terms of this Lease, Landlord shall have and
is hereby granted by Tenant a right of distress for rent, and a contractual
first lien and security interest upon all of Tenant's Property and all
Leasehold Improvements, and also upon all proceeds from the sale, transfer or
other disposition of any such property, and any replacements and substitutions
thereof, and proceeds thereof, and all proceeds of any insurance which may
accrue to Tenant by reason of damage to or destruction of any such property.
All exemption laws are hereby waived by Tenant. This lien is given in addition
to Landlord's statutory and common law liens and shall be cumulative thereto.
"Leasehold Improvements" shall be defined to mean all improvements installed or
constructed within the Demised Premises whether by or on behalf of either
Landlord or Tenant (exclusive of Tenant's trade fixtures), and as repaired,
replaced, altered or improved from time to time during the Lease Term,
including without limitation, any partitions, wall coverings, floors, floor
coverings, ceilings, lighting fixtures, and telephone, computer and/or data
system wiring or other improvements. "Tenant's Property" shall be defined to
mean all of Tenant's trade fixtures and all of Tenant's personal property,
including, but not limited to, all goods, wares, merchandise, inventory,
furniture, machinery, equipment, telecommunications and data transmission
systems (and all their components exclusive of wiring), business records,
accounts receivables and other personal property of Tenant in or about the
Demised Premises or that may be placed or kept therein during the Lease Term.

        (b) UCC Security Interest. This Lease shall also constitute a security
agreement under the Uniform Commercial Code of the District, State or
Commonwealth in which the Demised Premises are located. Upon the occurrence of
an event of default by Tenant under this Lease, Landlord shall have the option,
in addition to any other remedies provided herein or by law or at equity, to
enter the Demised Premises with or without the permission of Tenant and take
possession of any and all of Tenant's Property situated in or related to the
Demised Premises, without liability for trespass or conversion, and to enforce
the lien and security interest hereby granted in any manner provided by law.
Upon Landlord's request, Tenant will execute and deliver to Landlord UCC
Financing Statements to evidence the above-described lien in favor of Landlord.
Landlord shall be permitted from time to time to file such statements in the
appropriate City, County, District, State and/or Commonwealth offices to
perfect such lien. All expenses incurred by Landlord, including attorneys'
fees, to prepare and file such statements (and any extensions, renewals,
assignments, transfers, releases and terminations relating thereto) shall be
immediately reimbursed by Tenant upon demand. If Tenant fails to deliver such
UCC Financing Statements within ten (10) working days after Landlord's request,
Tenant by such failure irrevocably constitutes and appoints Landlord as its
special attorney-in-fact to execute and record the statements (and any
extensions, renewals, assignments, transfers, releases and terminations
relating thereto), the foregoing power of attorney being coupled with an
interest.

        (c) UCC Remedies Not Mandatory. Notwithstanding anything herein to the
contrary, Landlord shall not be required to exercise any of its remedies under
the Uniform Commercial Code as a result of the security interest granted to
Landlord herein in lieu of any other right or remedy Landlord may have under
this Lease, at law or in equity, including without limitation the right to deem
any or all of Tenant's Property abandoned and/or dispose of it pursuant to the
provisions of Section 12.8.

   12.10 INJUNCTIVE RELIEF. In the event of a breach by Tenant of any of the
covenants or provisions hereof, Landlord shall have the right of injunction and
the right to invoke any remedy allowed at law or in equity as if re-entry,
summary proceedings and other remedies were not herein provided; and in such
event Landlord shall be entitled to recover from Tenant, payable as Additional
Rent hereunder, any and all reasonable expenses as Landlord may incur in
connection with its efforts to secure such injunctive relief or other remedy at
law or in equity, including all costs and reasonable attorneys' fees.

   12.11 INDEPENDENT COVENANTS. If Landlord shall commence any proceeding based
upon non-payment of Base Annual Rent, Additional Rent or any other sums of any
kind to which Landlord may be entitled or which it may claim hereunder, Tenant
will not interpose any counterclaim, set-off, recoupment or other defense of any
nature or description in any such proceeding. The parties hereto specifically
agree that Tenant's covenants to pay Base Annual Rent, Additional Rent and any
other sums required hereunder are independent of all other covenants and
agreements of Landlord herein contained; provided, however, that this shall not
be construed as a waiver of Tenant's right to assert such a claim in any
separate action brought by Tenant. Tenant further waives any right or defense
which it may have to claim a merger.

   12.12 WAIVER OF REDEMPTION. Tenant hereby expressly waives any and all rights
of redemption granted by or under any present or future laws in the event of
Tenant being evicted or dispossessed for any cause, or in the event of Landlord
obtaining possession or a judgment for or other right to possession of the
Demised Premises and/or Tenant's Property by reason of the violation by Tenant
of any of the covenants and conditions of this Lease, or otherwise.

   12.13 ATTORNEYS' FEES. The parties hereto agree that wherever in this Lease
the Landlord is entitled to collect its "attorneys' fees", Landlord shall be
entitled to collect the entire amount of attorneys' fees actually incurred by
Landlord in enforcing its rights hereunder, and, wherever in this Lease the
Landlord is entitled to collect its "reasonable attorneys' fees", Landlord shall
be entitled to not less than twenty-five percent (25%) of any Base Annual Rent,
Additional Rent and/or other sums due Landlord in connection with the collection
thereof, as reasonable attorneys' fees and, in addition, with respect to actions
or claims pertaining to non-rent issues, Landlord shall be entitled to
reimbursement of the customary hourly billing rate of each attorney (and
non-attorney personnel working under such attorney's supervision) for the
reasonable time spent in enforcing (or attempting to enforce) any non-rent
obligation of Tenant hereunder, as reasonable attorneys' fees; provided,
however, the amount to be reimbursed by Tenant as attorneys' fees (reasonable or
otherwise) in any one matter shall never be less than One Thousand Dollars
($1,000).


                                       20
<PAGE>   27



13      SUBORDINATION

   13.1 SUBORDINATION. This Lease is subject and subordinate to all ground or
underlying leases and to all mortgages and/or deeds of trust and/or other
security interests (individually and collectively "mortgage") which may now or
hereafter affect the real property of which the Demised Premises form a part,
including all renewals, modifications, consolidations, replacements and
extensions thereof. This clause shall be self-operative and no further
instrument of subordination shall be required to effect this subordination.
Notwithstanding the foregoing, in confirmation of such subordination, Tenant
shall at Landlord's request execute and deliver to Landlord within ten (10)
business days after Landlord's request, any requisite or appropriate
certificate, subordination agreement or other document that may be reasonably
requested by Landlord or any other party requiring such certificate,
subordination agreement or document. If Tenant fails to execute such
certificate, subordination agreement or other document requested by Landlord or
other party within said ten (10) day period, Tenant by such (failure
irrevocably constitutes and appoints Landlord as its special attorney-in-fact
to execute such certificate, subordination agreement or other document on
Tenant's behalf, the foregoing power-of-attorney being deemed to be coupled
with an interest. Notwithstanding the foregoing, any lessor under any ground or
underlying lease and the party secured by any mortgage affecting the real
property of which the Demised Premises are a part, or any renewal,
modification, consolidation, replacement or extension thereof, shall have the
right to recognize this Lease and, in the event of any cancellation or
termination of such ground or underlying lease, or any foreclosure under any
mortgage, or any sale of the real property at foreclosure sale, or any transfer
of the real property by a deed in lieu of foreclosure, this Lease shall
continue in full force and effect at the option of the lessor under such ground
or underlying lease or, as applicable, the party secured by such mortgage, or
the purchaser at any foreclosure sale, or the party taking the real property
under a deed in lieu of foreclosure, such party being hereby authorized by
Tenant to exercise such option to cancel or continue this Lease in such party's
reasonable or unreasonable discretion. Tenant hereby consents to the right of
such party to effect the survival of this Lease. Tenant agrees that neither the
cancellation nor termination of any ground or underlying lease, nor the
foreclosure under any mortgage, nor the sale at foreclosure, nor the transfer
by a deed in lieu of foreclosure, shall, by operation of law or otherwise,
result in cancellation or termination of this Lease or the obligations of
Tenant hereunder, except in the sole option of the party herein granted such
option, which option may be exercised in said party's reasonable or
unreasonable discretion.

   13.2 ESTOPPEL CERTIFICATES. Tenant shall execute and return within ten (10)
business days any certificate that Landlord may request from time to time,
stating that this Lease is unmodified and in full force and effect, or in full
force and effect as modified, and stating the modification. The certificate
also shall state (a) the amount of the monthly installment of Base Annual Rent
and Additional Rent and the dates to which such rent has been paid in advance;
(b) the amount of any security deposit or prepaid rent; (c) that there is no
present default on the part of Landlord nor is there in existence any
condition, event, act or omission which with the giving of notice and/or the
passage of time will constitute a default on the part of Landlord, or attach a
memorandum stating in detail the factual circumstances of such default and/or
the basis under the Lease for such default; (d) that Tenant has no right to
set-off or recoupment and no defense or counterclaim against enforcement of its
obligations under this Lease; (e) that Tenant has no other notice of any sale,
transfer or assignment of this Lease or of the rentals; (f) that all
Construction Improvements and other work and improvements required of Landlord
has been completed and that the Construction Improvements and other work and
improvements are complete and satisfactory; (g) that Tenant is in full and
complete possession of the Demised Premises; (h) the date on which Tenant's
rental obligations commenced (excluding any periods of abatement) and the date
to which such rent has been paid; (i) that Tenant has not advanced any amounts
to or on behalf of Landlord which have not been reimbursed; (j) that Tenant
understands that this Lease has been collaterally assigned to Landlord's
mortgagee as security for a loan to Landlord; (k) that Base Annual Rent and
Additional Rent may not be prepaid more than one (1) month in advance without
the prior written approval of Landlord's mortgagee; and (l) such other items as
Landlord may reasonably request. Failure to deliver the certificate within the
aforesaid ten (10) business day period shall be conclusive upon Tenant for the
benefit of Landlord and any successor to or mortgagee or assignee of Landlord
that this Lease is in full force and effect and has not been modified except as
may be represented by the party requesting the certificate. If Tenant fails to
deliver the certificate within the aforesaid ten (10) business day period,
Tenant by such failure irrevocably constitutes and appoints Landlord as its
special attorney-in-fact to execute and deliver the certificate to any third
party, the foregoing power of attorney being deemed to be coupled with an
interest.

   13.3 ATTORNMENT. Tenant covenants and agrees that, in the event any ground
lessor, lessor of any underlying lease or subsequent purchaser of the Building
so requests or in the event of any foreclosure under any mortgage, or any
renewal, modification, consolidation, replacement or extension thereof, or in
the event of a sale at foreclosure, or in the event of any acceptance of any
deed in lieu of foreclosure, which may now or hereafter affect the real property
of which the Demised Premises are a part, Tenant shall attorn to any ground
lessor, lessor of any underlying lease or subsequent purchaser of the Building
or to the party secured by such mortgage, or any renewal, modification,
consolidation, replacement or extension thereof, and to any purchaser at any
foreclosure sale or party taking a deed in lieu of foreclosure, and at the sole
option of such party, which option may be exercised in said party's reasonable
or unreasonable discretion, this Lease shall continue as a direct lease between
Tenant herein and such landlord or its successor. In any case, such landlord or
successor under such ground or underlying lease or such secured party or
purchaser at foreclosure sale or party taking a deed in lieu of foreclosure
shall not be bound by any prepayment on the part of Tenant of the Base Annual
Rent or Additional Rent for more than one month in advance, so that Base Annual
Rent and Additional Rent shall be payable under this Lease in accordance with
its terms, from the date of the termination or transfer of the ground or
underlying lease or the foreclosure under such mortgage, or the date of
foreclosure sale or transfer by deed in lieu of foreclosure, as if such
prepayment had not been made. Further, such landlord or successor in interest
shall not be liable for damages for any act or omission of Landlord or any prior
landlord or be subject to any recoupments, offsets, counterclaims or defenses
which Tenant may have against Landlord or any prior landlord. Tenant shall,
upon request of such landlord or successor landlord, execute and deliver an
instrument or instruments confirming Tenant's attornment.

   13.4 MORTGAGEE RIGHTS.

        (a) Mortgagee Requirements. Tenant shall, at its own expense, comply
with all reasonable notices of Landlord's mortgagee or other financial
institution providing funds which are secured by a mortgage placed on the whole
or any part of the real property of which the Demised Premises are a part,
respecting all matters of occupancy, use, condition or maintenance of the
Demised Premises, provided the same shall not unreasonably interfere with the
conduct of Tenant's business nor materially limit or affect the rights of the
parties under this Lease. Tenant shall, if so directed by Landlord's mortgagee
or such other financial institution in writing, pay all Base Annual Rent,
Additional Rent and other sums owed to Landlord directly to such mortgagee or
other financial institution. Notwithstanding acceptance and execution of this
Lease by the parties hereto, the terms hereof shall be automatically deemed
modified, if so required, for the purpose of complying with or fulfilling the
reasonable requirements of any mortgagee or trustee named or


                                       21
<PAGE>   28

secured by a mortgage that may now or hereafter be placed upon or secured by the
real property of which the Demised Premises are a part or any part thereof, or
any other financial institution providing funds to finance or refinance the real
property of which the Demised Premises are a part; provided, however, that such
modification(s) shall not be in material derogation or diminution of any of the
rights of the parties hereunder, nor materially increase any of the obligations
or liabilities of the parties hereunder.

       (b) Notices to Mortgagee Tenant agrees to give Landlord's mortgagee and
any trustee named or secured by a mortgage a copy of any notice of default
served upon Landlord by Tenant, provided that prior to such notice Tenant has
been notified in writing (by way of Notice of Assignment of Rents and Leases, or
otherwise) of the names and addresses of such mortgagees and trustees. Notice
shall be provided to the mortgagees and trustees in the manner prescribed in
Section 24. Tenant further agrees that if Landlord shall have failed to cure
such default within the cure period provided in this Lease, if any, then the
mortgagees and trustees shall have an additional thirty (30) days within which
to cure such default, or if such default cannot be cured within that time, then
such additional time as may be necessary if within such thirty (30) days such
mortgagee or trustee has commenced and is diligently pursuing the remedies
necessary to cure such default (including, but not limited to, commencement of
foreclosure proceedings if necessary to effect such cure), in which event Tenant
shall not pursue its remedies while such cure is being diligently pursued.

14.    TENANT'S HOLDOVER

       14.1 WITH LANDLORD CONSENT. If Tenant continues, with the knowledge and
written consent of Landlord obtained at least thirty (30) days prior to the
expiration of the Lease Term, to remain in the Demised Premises after the
expiration of the Lease Term, then Tenant shall, by virtue of said holdover
agreement, become a tenant from month-to-month at the rent stipulated by
Landlord in said consent, or if none is stipulated, at the monthly rate of Base
Annual Rent and Additional Rent last payable under this Lease (adjusted in
accordance with the provisions of this Lease as if the holdover period were
originally included herein), commencing said monthly tenancy with the first day
next following the end of the Lease Term. All other terms and conditions of this
Lease shall apply to any holdover period(s). Tenant shall give to Landlord at
least thirty (30) days written notice of any intention to quit the Demised
Premises. Tenant shall be entitled to thirty (30) days written notice from
Landlord to quit the Demised Premises, except in the event of nonpayment of the
monthly installment of Base Annual Rent and/or Additional Rent in advance or of
the breach of any other covenant, term or condition of this Lease by Tenant, in
which event Tenant shall not be entitled to any notice to quit, the usual thirty
(30) days notice to quit being hereby expressly waived by Tenant.

       14.2 WITHOUT LANDLORD CONSENT. In the event that Tenant, without the
written consent of Landlord, shall hold over beyond the expiration of the Lease
Term, then Tenant hereby waives all notice to quit and agrees to pay to Landlord
for the period that Tenant is in possession after the expiration of this Lease,
a monthly charge which is three times the total monthly installment of Base
Annual Rent and Additional Rent in effect during the last month of the Lease
Term. Tenant expressly agrees to reimburse, defend, indemnify and hold Landlord
and Landlord's Agent harmless from all loss and damages, direct and
consequential, which Landlord or Landlord's Agent may incur in connection with
or in defense of claims by other persons or entities against Landlord,
Landlord's Agent or otherwise arising out of the holding over by Tenant,
including without limitation reasonable attorneys' fees which may be incurred by
Landlord or Landlord's Agent in defense of such claims. Acceptance of Base
Annual Rent, Additional Rent or any other sums due from Tenant hereunder or the
performance by Tenant of its obligations hereunder subsequent to the expiration
of the Lease Term, shall not constitute consent to any holding over. Landlord
shall have the right to apply all payments received after the expiration date of
the Lease Term toward payment for use and occupancy of the Demised Premises
subsequent to the expiration of the Lease Term and toward any other sums owed by
Tenant to Landlord, regardless of how such payment(s) may be designated by
Tenant. Landlord, at its option, may forthwith re-enter and take possession of
the Demised Premises without process, or by any legal process in force.
Notwithstanding the foregoing, if Tenant holds over, without Landlord's written
consent, due to acts of God, riot, or war, then such holdover shall be at the
total monthly installment of Base Annual Rent and Additional Rent applicable to
the last month of the Lease Term (adjusted in accordance with the provisions of
this Lease as if the holdover period were originally included herein), for the
duration of the condition (but not to exceed ten (10) days), but such continued
occupancy shall not create any renewal of the term of this Lease nor shall it
create a tenancy from year-to-year, month-to-month, or otherwise, and Tenant
shall be liable for and shall indemnify, defend and hold harmless Landlord and
Landlord's Agent against any loss and damages suffered by Landlord or Landlord's
Agent as described above. Any holdover period during which the Landlord and
Tenant are negotiating the terms and conditions of any holdover tenancy, new
lease or other matter, and/or for which Landlord and Tenant have failed to reach
an agreement as to the rent to be paid during such holdover period, shall
conclusively be deemed to be a holdover without the consent of Landlord for the
purpose of determining the rental to be paid and the obligations to be performed
by Tenant during such period.

15.    SECURITY DEPOSIT

       Tenant shall deposit with Landlord or Landlord's Agent simultaneously
with the execution of this Lease, the amount stipulated in Section 1.6 as a
security deposit. Provided Tenant is not in default in the payment of Base
Annual Rent, Additional Rent or any other charges due Landlord, and further
provided the Demised Premises are left in good condition, reasonable wear and
tear excepted, as described in Section 6.10, said deposit (which shall not bear
interest to Tenant) shall be returned to Tenant within sixty (60) days after the
termination of this Lease. Notwithstanding the foregoing, the full or partial
return by Landlord to Tenant of the security deposit shall at no time be deemed
to constitute a waiver by Landlord of any of Tenant's obligations under this
Lease, nor an acknowledgment by Landlord that any such obligations are limited
to the amount, if any, of the security deposit retained by Landlord. If Tenant
is in default or is otherwise indebted to Landlord hereunder or if the Demised
Premises are not left in good condition, or if Tenant has failed or refused to
remove Tenant's Property after Landlord's request to do so, then the security
deposit shall be applied to the extent available on account of sums due Landlord
or the cost of repairing damages to the Demised Premises or to remove Tenant's
Property. In the event the funds deposited with Landlord as security are applied
during the Lease Term on account of sums due Landlord or to the cost of
repairing damages or removing Tenant's Property, then Tenant shall, within
fifteen (15) days after demand by Landlord, deposit with the Landlord additional
funds to restore the security deposit to its original amount. In the event of
the sale or transfer of Landlord's interest in the Building, Landlord shall
have the right to transfer the security deposit to such purchaser or
transferee, in which event Tenant shall look only to the new landlord for the
return of the security deposit and Landlord shall thereupon be released from
all liability to Tenant for the return of such security deposit.





                                       22
<PAGE>   29

16.    QUIET ENJOYMENT

       So long as Tenant shall observe and perform the covenants and agreements
binding on Tenant hereunder, Tenant shall at all times during the term herein
granted, peacefully and quietly have and enjoy possession of the Demised
Premises without any encumbrance or hindrance by, from or through Landlord,
except as provided for elsewhere under this Lease. Nothing in this Section shall
prevent Landlord from performing alterations, improvements or repairs on other
portions of the Building not leased to Tenant or from performing alterations,
improvements or repairs within the Demised Premises in accordance with the
provisions of this Lease, nor shall performance of alterations, improvements or
repairs by Landlord, Landlord's Agent or any other tenant of the Building be
construed as a breach of this covenant by Landlord,

17.    SUCCESSORS

       All rights, remedies and liabilities herein given to or imposed upon
either of the parties hereto, shall extend to their respective heirs, executors,
administrators, personal representatives, successors and assigns. This provision
shall not be deemed to grant Tenant any right to assign this Lease or to sublet
the Demised Premises.

18.    WAIVER OF JURY TRIAL AND STATUTE OF LIMITATIONS

       Landlord and Tenant (and any guarantors and other parties with liability
for the performance of any or all of Tenant's obligations hereunder, as well as
any subtenants, assignees and licensees of Tenant) hereby waive trial by jury in
any action, proceeding or counterclaim brought by either of the parties hereto
against the other or in respect of any matter whatsoever arising out of or in
any way connected with this Lease, the relationship of Landlord and Tenant
hereunder, Tenant's use or occupancy of the Demised Premises, and/or any claim
of injury or damage. Tenant (and any guarantors and other parties with liability
for the performance of any or all of Tenant's obligations hereunder, as well as
any subtenants, assignees and licensees of Tenant) hereby waives the benefit of
any statute of limitation or other law limiting or prohibiting Landlord from
bringing any claim against Tenant (and/or any guarantors and/or other parties
with liability for the performance of any or all of Tenant's obligations
hereunder, as well as any subtenants, assignees and licensees of Tenant) arising
from or related to this Lease, the relationship of Landlord and Tenant and/or
the performance of Tenant's obligations hereunder at any time. Tenant (and any
guarantors and other parties with liability for the performance of any or all of
Tenant's obligations hereunder, as well as any subtenants, assignees and
licensees of Tenant) hereby agrees to submit to the personal jurisdiction of any
court of competent jurisdiction within the state, or the District of Columbia if
applicable, in which the Demised Premises and/or Landlord's principal place of
business is located.

19.    LIMITATION OF LANDLORD'S LIABILITY; NOTICE

       19.1 LANDLORD'S CONSENT. Notwithstanding anything to the contrary
contained in this Lease, if any provision of this Lease expressly or impliedly
obligates Landlord not to unreasonably withhold its consent or approval, an
action for declaratory judgment or specific performance will be Tenant's sole
right and remedy in any dispute as to whether Landlord has breached such
obligation or is required to give consent or approval. In no event shall
Landlord be liable for damages for any withholding of, any delay in providing,
or the conditioning of, any consent or approval.

       19.2 INDIVIDUAL LIABILITY. Tenant acknowledges and agrees that the
liability of Landlord with respect to any claim arising out of, related to, or
under this Lease shall be limited solely to its interest in the Building. No
personal judgment shall lie against the Landlord nor any partner of a
partnership constituting Landlord (if Landlord is a partnership) nor any
shareholder of Landlord (if Landlord is a corporation), and none of the same
will be personally liable with respect to any claim arising out of or related to
this Lease. If the Landlord is a partnership, any deficit capital account of any
partner and any partner's obligation to contribute capital shall not be deemed
an asset of the partnership. In the event of sale or other transfer of the
Landlord's interest in the Demised Premises and/or Building, Landlord shall
thereupon and without further act by either party be deemed released from all
liability and obligations hereunder arising out of any act or omission relating
to the Demised Premises, the Building or this Lease, occurring subsequent to the
sale or other transfer. The provisions hereof shall inure to the benefit of
Landlord's successors and assigns, including any mortgagee or trustee under a
deed of trust. The foregoing provisions are not intended to relieve Landlord
from the performance of any of Landlord's obligations under this Lease, but only
to limit the personal liability of Landlord, and its partners or shareholders,
as the case may be; nor shall the foregoing be deemed to limit Tenant's rights
pursuant to this Lease to obtain injunctive relief or specific performance with
respect to any obligations of Landlord hereunder.

       19.3 NOTICE IN EVENT OF LANDLORD'S DEFAULT. Notwithstanding anything to
the contrary in this Lease, in no event shall Landlord be deemed to be in
default in the performance of any covenant, condition or agreement herein
contained unless Tenant shall have given Landlord written notice of such
default, and Landlord shall have failed to cure such default within thirty (30)
days after such notice (or if such default is of such nature that it cannot be
completely cured within said thirty (30) days, if Landlord fails to commence to
cure within said thirty (30) days and thereafter proceed with reasonable
diligence and in good faith to effect such cure).

20.    AUTHORITY

       Landlord and Tenant hereby covenant each for itself, that each has the
full right, power and authority to enter into this Lease upon the terms and
conditions herein set forth. If Tenant signs as a corporation, each of the
persons executing this Lease on behalf of Tenant does hereby covenant and
warrant that Tenant is and shall be throughout the Lease Term, a duly authorized
and existing corporation, qualified to do business in the jurisdiction in which
the Demised Premises are located and is in good standing, that the corporation
has full right and authority to enter into this Lease, and that each of the
persons signing on behalf of the corporation were authorized to do so. If Tenant
signs as a partnership, each of the persons executing this Lease on behalf of
Tenant does hereby covenant and warrant that Tenant is a duly formed and validly
existing partnership, qualified to do business in the jurisdiction in which the
Demised Premises are located, and is in good standing, that the partnership has
full right and authority to enter into this Lease, and that each of the persons
signing on behalf of the partnership were authorized to do so.

21.    TENANT'S RESPONSIBILITY REGARDING HAZARDOUS SUBSTANCES

       21.1 HAZARDOUS SUBSTANCES. The term "Hazardous Substances", as used in
this Lease, shall include, without limitation, (a) "hazardous wastes", as
defined by the Resource Conservation and Recovery Act of 1976 as amended from
time to time, (b) "hazardous substances", as defined by the Comprehensive
Environmental Response Compensation and Liability Act of 1980, as amended from
time to time, (c) "toxic substances", as defined by the Toxic Substances Control
Act, as amended from time to time, (d) "hazardous materials", as defined by the
Hazardous Materials Transportation Act, as amended from time to time, (e) oil or
other petroleum products, (f) any substance whose presence could be detrimental
to the Building, its occupants or visitors, or the environment, (g) substances
requiring special handling, (h) flammables, explosives, radioactive materials,
asbestos, polychlorinated biphenlys (PCBs),


                                       23


<PAGE>   30


chlorofluorocarbons, chemicals known to cause cancer or reproductive toxicity,
pollutants and contaminants, (i) any infectious and/or hazardous medical waste
as the same may be determined from time to time, and (j) any other substances
declared to be hazardous or toxic under Laws (hereinafter defined) now or
hereafter enacted or promulgated by any Authorities (hereinafter defined).

21.2   TENANT'S RESTRICTIONS. Tenant shall not cause or permit to occur:

       (a) Violations. Any violation of any federal, state and local laws,
ordinances, regulations, directives, orders, notices and requirements now or
hereafter enacted or promulgated regulating the use, generation, storage,
handling, transportation, or disposal of Hazardous Substances ("Laws"), now or
hereafter enacted, related to environmental conditions on, under, or about the
Demised Premises, the Building and/or the Complex, or arising from Tenant's use
or occupancy of the Demised Premises, Tenant's Property, or Leasehold
Improvements, including, but not limited to, soil and ground water conditions;
and/or

       (b) Use. The use, generation, release, manufacture, refining, production,
processing, storage, or disposal of any Hazardous Substances on, under, or about
the Demised Premises, the Building and/or the Complex, or the transportation to
or from the Demised Premises of any Hazardous Substances, without the prior
written consent of Landlord, such consent to be granted or withheld in
Landlord's sole and absolute discretion, and, if granted, Tenant's activities
shall be in strict compliance with all Laws.

21.3   AFFIRMATIVE OBLIGATIONS.

       (a) Compliance with Laws. Tenant shall, at Tenant's own expense, comply
with all Laws. Tenant shall, at Tenant's own expense, make all submissions to,
provide all information required by, and comply with all requirements of all
federal, state and local governmental and regulatory authorities (the
"Authorities") under the Laws. Tenant shall promptly provide Landlord with a
copy of all such submissions and information requests.

       (b) Clean-Up Plans. Should any Authority or any third party demand that a
removal or clean-up plan be prepared and that a removal or clean-up be
undertaken because of any deposit, spill, discharge, release, misuse,
prohibition on continued use, act or failure to act with respect to any
Hazardous Substances relating to, occurring on or arising out of Tenant's use or
occupancy of the Demised Premises, Tenant's Property or Leasehold Improvements,
then Tenant shall, at Tenant's own expense, prepare and submit the required
plans and all related bonds and other financial assurances, and Tenant shall
carry out all such removal and clean-up plans within the time limits set by any
Authority or other party. Tenant shall promptly provide Landlord with copies of
notices received from any Authority or third party, and of all removal and
clean-up plans, bonds, and related matters.

       (c) Information Requests. Tenant shall promptly provide all information
regarding the use, generation, storage, transportation or disposal of Hazardous
Substances that is required hereunder or is requested by Landlord. If Tenant
fails to fulfill any duty imposed under this Section 21 within a reasonable time
(or any shorter period of time if so required by any Authority), Landlord may
(but shall not be obligated to) do so and all costs associated therewith shall
constitute Additional Rent hereunder and shall be immediately due and payable to
Landlord, together with interest thereon calculated at the rate of twenty-four
percent (24%) per annum. In such case, Tenant shall cooperate with Landlord in
order to prepare all documents Landlord deems necessary or appropriate to
determine the applicability of the Laws to the Demised Premises, Tenant's use
thereof and Tenant's Property and Leasehold Improvements, and for compliance
therewith, and Tenant shall execute all documents promptly upon Landlord's
request. No such action by Landlord and no attempt made by Landlord to mitigate
damages under any Laws shall constitute a waiver of any of Tenant's obligations
under this Section 21.

   21.4 Tenant's Indemnity. Tenant shall indemnify, defend, and hold harmless
Landlord, Landlord's Agent, and their respective officers, directors,
beneficiaries, shareholders, partners, agents and employees from all fines,
suits, procedures, claims and actions of every kind, and all costs associated
therewith (including attorneys' and consultants' fees) arising out of or in any
way connected with any deposit, spill, discharge, release, misuse, prohibition
or continued use, act or failure to act, with respect to any Hazardous
Substances or other failure to comply with the Laws which arise at any time from
Tenant's use or occupancy of the Demised Premises or Tenant's Property or the
Leasehold Improvements, or from Tenant's failure to provide all information,
make all submissions, and take all steps required by all Authorities under the
Laws and all other related laws.

   21.5 Survival of Obligations. Tenant's obligations and liabilities under this
Section 21, and the obligations of all guarantors and other parties with
liability for the performance of any or all of Tenant's obligations hereunder,
shall survive the expiration or earlier termination of this Lease.

22.    JOINT AND SEVERAL LIABILITY

       In the event that two or more individuals, corporations, partnerships or
other business associations (or any combination of two or more thereof) shall
sign this Lease as Tenant or guarantee this Lease as guarantors or are otherwise
liable for the performance of any or all of Tenant's or any guarantor's
obligations, the liability of each such individual, corporation, partnership or
other business association to pay Base Annual Rent, Additional Rent and any
other sums due hereunder and to perform all or any other obligations hereunder
shall be deemed to be joint and several. In like manner, in the event that the
Tenant named in this Lease shall be a partnership or other business association,
the members of which are by virtue of statute or general law subject to personal
liability, then, and in that event, the liability of each such member shall be
deemed to be joint and several. Notwithstanding any other provisions hereof, or
of any rule or provisions of law, the failure or refusal by Landlord to proceed,
in the event of a breach or default by Tenant, against all the individuals,
corporations, partnerships or other business associations comprising the Tenant
(or any combination of two or more thereof) or against Tenant or against one or
more of the guarantors or other parties with liability for the performance of
any or all of Tenant's or any guarantor's obligations, shall not be deemed to be
a release or waiver of any rights which Landlord may possess against such other
individuals, corporations, partnerships or other business associations not so
proceeded against, nor shall the granting by Landlord of a release of, or
execution of a covenant not to sue, any one or more of the individuals,
corporations, partnerships, or other business associations comprising the Tenant
(or any combination of two or more thereof) or the guarantors or other parties
with liability for the performance of any or all of Tenant's or any guarantor's
obligations, constitute a release or waiver, in whole or part, of any rights
which Landlord may possess against such other individuals, corporations,
partnerships, or associations not so released or granted a covenant not to sue.




                                       24




<PAGE>   31
23.    DEFINITIONS

       23.1 PRONOUNS. Feminine or neuter pronouns shall be substituted for
those of the masculine form, and the plural shall be substituted for the
singular number, in any place or places herein in which the context may require
such substitution or substitutions. Landlord and Tenant herein for convenience
have been referred to in the neuter form.

       23.2 DEMISED PREMISES. Wherever the word "premises" or the phrase
"demised premises" is used in this Lease, it shall refer to the Demised
Premises described in Section 1.1, unless the context clearly requires
otherwise.

       23.3 LEASE TERM. Wherever the phrase "Lease Term" or the phrase "term of
this Lease" is used in this Lease, it shall refer to the Lease Term described in
Section 1.2(a) and any extensions and renewals thereof validly and timely
exercised by Tenant, unless the context clearly requires otherwise.

       23.4 TENANT'S PROPERTY. Wherever the phrase "Tenant's Property" is used
in this Lease, it shall refer to the Tenant's Property described in Section
12.9(a), unless the context clearly requires otherwise.

       23.5 LEASEHOLD IMPROVEMENTS. Wherever the phrase "Leasehold Improvements"
is used in this Lease, it shall refer to the Leasehold Improvements described
in Section 12.9(a), unless the context clearly requires otherwise.

24.    NOTICE TO PARTIES

       24.1 ADDRESSES FOR NOTICES. All notices required or desired to be given
hereunder by either party to the other shall be in writing and personally
delivered or given by overnight express delivery service or by certified or
registered mail (delivery and/or postage charges prepaid) and addressed as
specified in Section 1.9. Either party may, by like written notice, designate a
new address to which such notices shall be directed.

       24.2 EFFECTIVE DATE OF NOTICE. Notices personally delivered shall be
deemed effective upon delivery; notices sent by certified or registered mail
shall be deemed effective upon the earlier of (i) the date of receipt or
rejection by the addressee, or (ii) three (3) days following the date of
mailing (excluding Sundays and holidays on which mail is not delivered by the
United States Postal Service). Notwithstanding the foregoing, any notice
pertaining to a change of address of a party shall be deemed effective only
upon receipt or rejection by the party to whom such notice is sent.

25.    NOTICE TO MORTGAGEES

       In addition to any notices required by Section 13.4, if any mortgagee
shall notify Tenant that it is the holder of a mortgage affecting the Demised
Premises and that it is requesting Tenant to provide the mortgagee with copies
of notices sent by Tenant to Landlord, no notice, request or demand thereafter
sent by Tenant to Landlord shall be effective unless and until a copy of the
same shall also be sent to such mortgagee in the manner prescribed in Section
24 and to such address as such mortgagee or trustee shall designate.

26.    SPECIAL PROVISIONS; EXHIBITS

       26.1 INCORPORATION IN LEASE. It is agreed and understood that any Special
Provisions and Exhibits referred to in Sections 1.10 and 1.11, respectively,
and attached hereto, form an integral part of this Lease and are hereby
incorporated by reference.

       26.2 CONFLICTS. If there is a conflict between a Special Provision
hereto and the Exhibits, Specific Provisions or General Provisions of this
Lease, the Special Provision shall govern. If there is a conflict between a
Specific Provision and the Exhibits or General Provisions of this Lease, the
Specific Provision shall govern. If there is a conflict between the Exhibits
and the General Provisions, the Exhibits shall govern.

27.    CAPTIONS

       All section and paragraph captions herein are for the convenience of the
parties only, and neither limit nor amplify the provisions of this Lease.

28.    ENTIRE AGREEMENT; MODIFICATION

       This Lease, all Exhibits, and the Specific and Special Provisions
incorporated herein by reference are intended by the parties as a final
expression of their agreement and a complete and exclusive statement of the
terms thereof, all negotiations, considerations and representations between the
parties having been incorporated herein. No course of prior dealings between
the parties or their officers, partners, employees, agents or affiliates shall
be relevant or admissible to supplement, explain or vary any of the terms of
this Lease, the Exhibits and the Specific and Special Provisions. Acceptance
of, or acquiescence in, a course of performance rendered under this or any
prior agreement between the parties, their agents or their affiliates shall not
be relevant or admissible to determine the meaning of any of the terms of this
Lease, the Exhibits and the Specific and Special Provisions. Tenant hereby
acknowledges that Landlord, Landlord's Agent and their respective agents and
employees made no representations, warranties, understandings or agreements
pertaining to the condition of the Building or the Demised Premises, or
otherwise, which have induced Tenant to execute, or have been relied upon by
Tenant in the execution of this Lease, other than those specifically set forth
herein. This Lease can be modified only by a writing signed by both parties
hereto. The language of this Lease shall in all cases be construed as a whole
and according to its fair meaning, and not strictly for or against either
Landlord or Tenant. The interpretation or construction of this Lease shall be
unaffected by any argument or claim, whether or not justified, that this Lease
has been prepared, wholly or in substantial part, by or on behalf of Landlord
or Tenant. Tenant acknowledges that it has had, or has had the opportunity to
have, legal counsel of Tenant's choice to negotiate on behalf of (and/or
explain to) Tenant the provisions of this Lease. Any consent or approval
required or desired of Landlord, or any decision under this Lease committed to
the discretion of Landlord hereunder, may be withheld, delayed, conditioned or
exercised by Landlord in its sole, absolute and arbitrary discretion unless the
provision of this Lease requiring such consent or approval, or decision under
this Lease committed to the discretion of Landlord, expressly states that
Landlord shall not withhold, delay, condition or exercise such consent,
approval or discretion unreasonably.

                                       25


<PAGE>   32

29.    GOVERNING LAW; SEVERABILITY

       This Lease shall be governed by and construed in accordance with the laws
of the Commonwealth of Virginia. The unenforceability, invalidity, or illegality
of any provision herein shall not render any other provision herein
unenforceable, invalid, or illegal.


30.    BINDING EFFECT OF LEASE

       The submission of an unsigned copy of this document to Tenant for
examination or signature shall not constitute an option, reservation or offer
to lease space in the Building. This Lease shall become effective and binding
only upon execution and delivery by both Landlord and Tenant, and shall be
enforceable in accordance with its terms from and after the date this Lease is
fully executed and delivered by Landlord and Tenant.

31.    FORCE MAJEURE

       Landlord is in any way delayed or prevented from performing any
obligation due to fire, act of God, governmental act, or failure to act, labor
dispute, inability to procure materials or any cause beyond Landlord's
reasonable control (whether similar or dissimilar to the foregoing named
events), then the time for performance of such obligation shall be excused for
the period of such delay or prevention and extended for a period equal to the
period of such delay or prevention.

32.    RECORDATION

       Neither this Lease nor a memorandum hereof shall be recorded by Tenant.
Any violation of this Section shall be a default hereunder and Tenant agrees to
pay all costs and expenses, including attorneys' fees, necessary to remove this
Lease or any memorandum hereof from record. Tenant irrevocably constitutes and
appoints Landlord as its special attorney-in-fact to prepare, execute and record
such instrument(s), the foregoing power of attorney being deemed to be coupled
with an interest.

33.    TIME OF ESSENCE

        Tenant acknowledges that time is of the essence in its performance of
any and all obligations, terms and provisions of this Lease.


34.    BROKERS

       Tenant represents and warrants that it did not retain, nor consult with,
any broker or real estate salesperson (other than Landlord's Agent) with
respect to this Lease. Tenant agrees to indemnify and hold Landlord and
Landlord's Agent harmless from and against claims for brokerage or other
commissions and any claim of, or right to, a lien under applicable law relating
to real estate broker liens, arising by reason of a breach by Tenant of the
foregoing representation and warranty. Tenant agrees to pay, or upon demand
reimburse Landlord and Landlord's Agent for, all costs and expenses, including
attorneys' fees, necessary to remove from record any lien filed against the
rents payable pursuant to this Lease and/or against the Demised Premises and/or
the Building, by reason of a breach by Tenant of the foregoing representation
and warranty.

35.    RELATIONSHIP OF LANDLORD AND TENANT

       Nothing in this Lease shall be interpreted or construed as creating any
partnership, joint venture, agency or any other relationship between the
parties, other than that of landlord and tenant.


                                      26
<PAGE>   33

36.    RENT

       36.1 In Section 2.1(a), in the fifth line, delete 'by electronic ...
otherwise'.

       36.2 Section 2.1(b) is deleted entirely.

       36.3 In Section 2.2(a)(i), in the fifth line, delete the parenthetical
phrase; and at the end of the paragraph, add: "If assessments may be paid in
installments, Tenant's pro rata share of such assessment shall be so charged,
whether Landlord actually pays in full or in installments. Notwithstanding
anything to the contrary, Tenant shall not be obligated to pay any increase in
Real Estate Taxes which is caused solely by the sale or transfer of the Demised
Premises. If at anytime during the term of the Lease, the Landlord transfers
ownership or refinances the Demises Premises, any increase in Real Estate Taxes
occasioned solely by such transfer or refinance shall be the sole obligation of
Landlord or Landlord's successor in interest.".

       36.4 In Section 2.2(a)(ii), at the end of the paragraph, add: "If Real
Estate Taxes accrued during a Fiscal Year are subsequently reduced by any
application or proceeding brought by or on behalf of Landlord for reduction in
the amount of Real Estate Taxes payable by Landlord, the Real Estate Taxes
deemed to have been accrued during said Fiscal Year shall be decreased and
Landlord shall refund to Tenant any excess Additional Rent previously paid by
Tenant for said Fiscal Year during the Lease Term, based upon the reduced amount
of Real Estate Taxes deemed accrued for said Fiscal Year.".

       36.5 Section 2.2(a)(iii) is deleted entirely.

       36.6 In Section 2.2(b)(i), in the sixth line, after 'Taxes' insert "not
to exceed the value of the savings"; in the eighth line, after 'Expenses' insert
"not to exceed the value of the savings"; and in the eighth and ninth lines,
delete 'at the option of Landlord,'.

       36.7 In Section 2.2(b)(ii), in the last line, after 'commissions;' insert
"costs of repairs, restoration, replacements or other work occasioned by fire,
windstorm or other insured casualty (whether such destruction be total or
partial) to the extent of insurance proceeds therefor; the cost of repairs,
etc., occasioned by the exercise by governmental authorities of the right of
eminent domain, whether such taking be total or partial, to the extent of any
condemnation awards; costs occasioned by intentional tort of Landlord, or any
subsidiary or affiliate of Landlord, or any employee or agent of same or the act
of any other tenant in the Building, or any other tenant's agents, employees,
licensees or invitees, to the extent Landlord recovers the applicable cost from
such person; leasing commissions, attorneys' fees (except for those reasonable
attorneys' fees directly related to Operating Expenses or Real Estate Taxes);
expenses incurred in connection with negotiations for leases with tenants, other
occupants, or prospective tenants or other occupants of the Building, or similar
costs incurred in connection with disputes with tenants, other occupants, or
prospective tenants, or similar costs and expenses incurred in connection with
negotiations or disputes with management agents, purchasers or mortgagees of the
Building; allowances, concessions and other costs and expenses incurred in
completing, fixturing, furnishing, renovating or otherwise improving, decorating
or redecorating space for tenants (including Tenant), prospective tenants or
other occupants and prospective occupants of the Building, or vacant, leasable
space in the Building; costs or expenses relating to another tenant's or
occupant's space which were incurred in rendering any service or benefit to such
tenant that was not available to Tenant; payments of principal and interest or
other finance charges made on any debt and rental payments made under any ground
or underlying lease or leases; costs incurred in connection with the sale,
financing, refinancing, mortgaging, selling or change of ownership of the
Building, including attorneys' and accountants' fees, closing costs, title
insurance premiums, transfer taxes and interest charges; costs, fines, interest,
penalties, legal fees or costs of litigation incurred due to the late payments
of taxes, utility bills and other costs incurred by Landlord's failure to make
such payments when due; costs incurred by Landlord for trustees fees,
partnership organizational expenses and accounting fees (except accounting fees
relating solely to the ownership and operation of the Building); Landlord's
general corporate overhead and general and administrative expenses; any
compensation paid to clerks, attendants or other persons in commercial
concessions operated by Landlord or in the parking garage of the Building;
rentals and other related expenses incurred in leasing air conditioning systems,
elevators or other equipment ordinarily considered to be of a capital nature
(except for equipment not affixed to the Building which is used in providing
janitorial or similar services); the

                                       27

<PAGE>   34
rent for Landlord's on-site management or leasing office, or any other offices
or spaces of Landlord or any related entity; Landlord's income and franchise
taxes; special assessments and other business taxes except those business taxes
which relate solely to the operation of the Building; all amounts which would
otherwise be included in Operating Expenses which are paid to any affiliate or
subsidiaries of Landlord, or any representative, employee or agent of same, to
the extent the costs of such services exceed fair market value; except the
management fee paid to Landlord's Agent, all other fees for management of the
Building; costs or expenses of utilities directly metered to tenants of the
Building and payable separately by such tenants; costs incurred (less costs of
recovery) for any items to the extent covered by a manufacturer's materialman's,
vendor's or contractor's warranty (a "Warranty") which are paid by such
manufacturer, materialman, vendor or contractor; electric power costs for which
any tenant directly contracts with the local public service company; services
provided and costs incurred in connection with the operation of the parking
garage or retail or the ancillary operations owned, operated or subsidized by
Landlord; rental for any space in the Building set aside for conference
facilities, storage facilities or exercise facilities; wages and salaries for
off-site employees and employees at the Building above the level of building
manager;".

                36.8    Section 2.2(b)(iii) is deleted entirely.

                36.9    In Section 2.3(c), in the first line, before `Landlord'
insert "and within one hundred eighty (180) days thereof, but without forfeiture
or waiver of Landlord's rights to Additional Rent if such deadline is not met,";
and in the penultimate line, before `for' insert "within six (6) months'.

                36.10   In Section 2.3(d), in the first line, delete `thirty
(30)' and substitute "ninety (90)"; and at the end of the paragraph, add: "In
the event Tenant asserts in a timely fashion a specific error in the statement
of Operating Expenses submitted by Landlord, Tenant shall have the right to
examine, or have its accountant examine, at the office of Landlord's accountant
the books and records relating to the error specifically asserted from which
such statement has been prepared. No such examination shall extend the time for
payments due in accordance with this Section 2.3, however. Tenant shall pay upon
demand a reasonable sum to reimburse Landlord for the costs of services of
Landlord's accountant in cooperating and assisting in the examination. If the
specific error asserted amounts to more than five percent (5%) in the Operating
Expenses statement and Tenant is found to have been correct, Landlord shall bear
its and Tenant's reasonable accountants' costs.".

                36.11   In Section 2.9, in the second line, before `it' insert
"written notice from Landlord that"; and in the penultimate line, delete
`eighteen percent (18%)' and substitute "twelve percent (12%)".


        37.     ACCRUAL OF RENT OBLIGATION

                37.1    Tenant shall be obligated for the payment of Base
Annual Rent and Additional Rent pursuant to Sections 1.3 and 1.5 on the
Commencement Date, regardless of any time required to construct, alter or
redecorate the Demised Premises to Tenant's requirements.


        38.     PARKING

                38.1    Landlord agrees to arrange for parking in the garage of
the Building for up to ninety-six (96) automobiles of Tenant or Tenant's
employees, which parking shall be made available upon Tenant's or its employees'
payment of the prevailing monthly rate for such service, which is currently
Fifty and 00/100 Dollars ($50.00) per automobile.


                                       28


<PAGE>   35




        39.     RENEWAL OPTION

                39.1    Provided that Tenant has not been in default beyond any
cure period of any of the terms and conditions of this Lease in the twelve
months before the date Tenant gives written notice as provided below and
thereafter through the commencement date of the extended term, and further
provided that Tenant gives written notice to Landlord on or before November 1,
2010, time being of the essence, Tenant shall have the right to extend the term
of this Lease for a further term of Five (5) years from November 1, 2011 to
October 31, 2016. Such extension shall be under the terms, covenants and
conditions, including a new Base Year for Additional Rent of 2010, the fair
market value base annual rent then in effect as of the commencement of the
extended lease term, and an agreed-upon formula for additional rent, all of
which shall be agreed to by the parties. Tenant's rights under this Section
shall be contingent on Tenant occupying a substantial portion (51% or more) of
the Demised Premises on the date Tenant gives written notice as provided above
and on the commencement date of the extended term.

                39.2    If Landlord and Tenant fail to agree on such new terms,
covenants and conditions, including the fair market value base annual rent and a
formula for additional rent for the extended term, by November 30, 2010, each
shall appoint, at its own expense, a member of the Washington D.C. Association
of Realtors who is knowledgeable in office rentals. These appointees shall
appoint a third person with the same qualifications. The cost of the third
appointee shall be borne equally by Landlord and Tenant. Each appointee shall
determine the fair market value base annual rent for the Demised Premises for
the extended Term. The average of the three figures arrived at by the appointees
for the fair market value base annual rent for the extended Term shall be used
as the base annual rent for the extended term. The appointees shall also agree
upon a formula for calculating additional rent payable during the extended term.
If they cannot agree on a formula by the time the base annual rent for the
extended term is determined, the formula for Additional Rent in this Lease for
the initial Lease Term shall be used.

                39.3    For the purposes of determining the base annual rent
rate and additional rent rate for the Renewal Option and Right of First Offering
in Sections 39 and 65, respectively, "fair market value" shall be defined as the
rent stipulated in leases signed within twelve (12) months prior to beginning of
the renewal term (or, as applicable, the lease period for the additional space),
for a term comparable to that of the renewal term (or, as applicable, the lease
period for the additional space), for space of a size close to that of the
Demised Premises (or, as applicable, the additional space), with comparable
finish and quality, in buildings of comparable size, quality, age, and location
in the Tysons Corner, Virginia submarket. "Fair market value" shall reflect any
landlord concessions such as rent waivers, annual escalations, pass-throughs,
limitations on escalations and pass-throughs, cash contributions and brokerage
commissions. In determining the "fair market value", it shall be assumed that
such concessions are to be provided to Tenant in a manner consistent with the
then-prevailing practices in buildings managed by Landlord's Agent.


        40.     LANDLORD'S CONTRIBUTION

                40.1    Provided Tenant is not then in monetary default of any
of the terms or conditions of this Lease, beyond applicable notice and cure
periods, Landlord shall reimburse Tenant for Construction Improvements completed
by Tenant or its contractors, if any, in the Demised Premises. This
reimbursement shall be in an amount which, together with sums owed by Tenant to
Landlord's contractors, if any, does not exceed Two Hundred Sixty-Six Thousand
Seven Hundred Fifty and 00/100 Dollars ($266,750.00) ("Landlord's
Contribution"). This reimbursement shall be paid to Tenant within forty-five
(45) business days after presentation by Tenant of paid receipted invoices
approved by Tenant for such Construction Improvements, all required certificates
of occupancy and inspection approvals for the Demised Premises, and final waiver
of lien forms executed by all of Tenant's contractors and their subcontractors.
Sums owed by Tenant to Landlord's contractors, if any, shall be paid directly to
Landlord's contractors by Landlord up to, and charged against, Landlord's
Contribution.








                                       29

<PAGE>   36




                40.2    Provided Tenant is not then in monetary default
hereunder beyond applicable cure periods, Tenant may apply up to Fifty-Three
Thousand Three Hundred Fifty and 00/100 Dollars ($53,350.00) of the Landlord's
Contribution toward relocation expenses, space planning, architectural and
engineering plans for the Demised Premises.


        41.     SPACE PLANNING, ARCHITECTURAL AND ENGINEERING PLANS

                41.1    Tenant, at its option, may elect to use the Building
architect to do its space planning and preparation of working drawings, or use
its own planner. In either case, such costs shall be paid by Tenant or deducted
from the Landlord's Contribution hereinabove. Further, Tenant will use
Landlord's engineers to prepare all mechanical, plumbing and electrical working
drawings at the reasonable fair market rate with the understanding that the cost
will be paid for by Tenant or deducted from the Landlord's Contribution.


        42.     REASONABLENESS OF LANDLORD AND TENANT

                42.1    Provided Tenant is not then in default of any of the
terms or conditions of this Lease beyond any applicable cure period, then
notwithstanding anything to the contrary in this Lease, whenever Landlord's
consent or approval is required hereunder, it shall not be unreasonably
withheld, conditioned or delayed. Whenever Tenant's consent or approval is
required hereunder, it shall not be unreasonably withheld, conditioned or
delayed.


        43.     CONSTRUCTION OF PREMISES AND OCCUPANCY

                43.1    In Section 3.1, delete the first, third and fourth
sentences entirely.

                43.2    Section 3.1(a)(i) is deleted entirely.

                43.3    In Section 3.1(a)(ii), delete the first three (3)
sentences entirely.

                43.4    In Section 3. 1(a)(iii), delete the first, penultimate
and last sentences entirely.

                43.5    In Section 3.1(b), in the third line, insert a period
after `Date' and delete the remainder of the paragraph.

                43.6    Section 3.1(c) is deleted entirely.

                43.7    In Section 3.2, in the tenth line, delete `one (1) year'
and substitute "eighteen (18) months", and after the second `Landlord' insert
"or Tenant"; in the eleventh line, delete both phrases of `to Tenant'; and in
the fourteenth line, after `Lease' insert a period and delete the rest of the
sentence.

                43.8    Notwithstanding any provisions to the contrary in
Section 3.2, Tenant shall have the right to enter Suite 400 on November 1, 2001
to make Leasehold Improvements and install Tenant's Property. Such use shall be
without liability for Base Annual Rent or Additional Rent pursuant to Sections
1.3, 1.4, 1.5, 2.1 and 2.2 during such period, but subject to all other terms,
covenants, conditions and provisions of this Lease.

                43.9    Notwithstanding anything to the contrary in Section 3.3,
only in the event SMC performs all of Tenant's remodeling, Landlord, with
Tenant's cooperation, will obtain the occupancy permit.

                43.10   Section 3.4 is deleted entirely.


                                      30
<PAGE>   37

       43.11 Tenant shall select its own contractors to remodel any portion of
the Demised Premises, subject to Landlord's approval of said contractors and the
working drawings. Tenant shall submit to Landlord for Landlord's reasonable
approval the qualifications of Tenant's intended contractors and the working
drawings. Smith Management Construction ("SMC") shall be entitled to bid for
Tenant's work. Tenant's contractors' work shall be performed in accordance with
Section 6.4 and shall be under the supervision and control of Landlord or its
designated agent with respect to access to the Demised Premises, permitted use
of elevators, approval of plans, inspection by governmental authorities, and
work that will or may affect the Systems. Tenant shall provide Landlord with
approved invoices for such remodeling work from Tenant's contractors or vendors
and all required building inspection approvals and certificates of occupancy.
Provided Tenant is not then in monetary default of any of the terms or
conditions of this Lease beyond applicable cure periods, and provided that
executed final waiver of lien forms have been received by Landlord from all of
Tenant's contractors and their subcontractors, Landlord shall then pay for such
expenses, which payment, when added to amounts payable to Landlord and/or its
contractors, if any, does not exceed the Two Hundred Sixty-Six Thousand Seven
Hundred Fifty and 00/100 Dollars ($266,750.00).


   44. SUBLETTING AND ASSIGNMENT

       44.1 In Section 4.1, in the twenty-fourth line, after 'Lease' insert ",
beyond any applicable cure period,".

       44.2 Provided Tenant is not then in monetary default of any of the terms
or conditions of this Lease, beyond applicable cure periods, then
notwithstanding anything to the contrary in the first sentence of Section 4.1,
Tenant shall not be required to obtain Landlord's consent to assign this Lease
or sublet all or any part of the Demised Premises to any parent, subsidiary or
affiliated company, or any company that results from a merger or consolidation
with Tenant or to any entity that acquires all of Tenant's assets as a going
concern of the business of Tenant, as long as the assignee/sublessee is a bona
fide entity and assumes the obligations of Tenant, but Tenant immediately shall
furnish Landlord with written notice and a fully-executed copy of any such
assignment or sublease agreement, together with a floor plan of the sublet area.
Any such assignment or subletting shall be subject to the remaining provisions
of Sections 4.1, 4.3, 4.4, 4.6 and 4.7.

       44.3 Provided Tenant first obtains the written consent of the Landlord to
such sublease or assignment as required by Section 4 and further provided that
Tenant is not in default beyond the applicable cure period of any of the terms
or conditions of this Lease on the date each rent payment is due pursuant to
such sublease or assignment, then notwithstanding Section 4.3, only Fifty
Percent (50%) of any rent and other consideration accruing to Tenant as a result
of each such sublease or assignment which is in excess of the pro rated portion
of Base Annual Rent and Additional Rent then being paid by Tenant for the
Demised Premises or portion thereof being sublet pursuant to said sublease or
assignment shall be paid by Tenant to Landlord monthly as Additional Rent.
Tenant shall be permitted to deduct the reasonable advertising costs, reasonable
brokerage commissions and reasonable remodeling costs in calculating Landlord's
share of the net excess rent and other consideration to be paid to Landlord
pursuant to this Section. Tenant shall provide documentation of such expenses to
Landlord at the time Tenant requests Landlord's giving consent to the subletting
or assignment.

       44.4 In Section 4.2, in the third and fourth lines, delete 'ninety (90)'
and substitute "thirty (30)"; and in both the sixth and seventh lines, after
'Premises' insert "for the remaining Lease Term only".

       44.5 In Section 4.5(a), in the first line, after 'transferee', insert
",in those instances in which Landlord's recapture rights may be applicable
pursuant to Section 4.2,"; and in the third line, before 'request' insert
"reasonably".

       44.6 In Section 4.5(b), in the first line, after 'transferee', insert
",in those instances in which Landlord's recapture rights may be applicable
pursuant to Section 4.2,".



                                       31

<PAGE>   38

       44.7 Section 4.5(g) is deleted entirely.

       44.8 In Section 4.5(h), after 'default,' insert "beyond any applicable
cure period,".

       44.9 In Section 4.7, in the first line, after 'Lease,' insert "beyond any
applicable cure period,".


   45. SERVICES AND UTILITIES

       45.1 In Section 5.1, in the last line, after 'Lease' insert "unless the
Demised Premises are rendered untenantable by such failure, suspension, delay or
interruption of services for five (5) consecutive business days due to
Landlord's negligence or willful misconduct, in which event Tenant may abate
paying Base Annual Rent from said fifth (5th) day until such service is
restored".

       45.2 For purposes of Section 5.1, the following are the legal public
holidays for the Building: New Year's Day, Martin Luther King, Jr., Day,
Inauguration Day, Presidents' Day, Memorial Day (observed), Independence Day,
Labor Day, Columbus Day (observed), Veterans' Day (observed), Thanksgiving Day
and Christmas Day.

       45.3 In Section 5.2, in the last line, after 'required' insert "on
Sundays and holidays only".

       45.4 In Section 5.3(a), in the fifth line, before 'Landlord' insert
"Subject to Tenant's security requirements,"; and in the sixth line, before 'to'
insert "after reasonable notice".

       45.5 In Section 5.3(c), in the third line, delete 'The' and insert "If
excess electric consumption is established by such meters or survey, then the";
and in the fourth line, after the first 'Tenant' insert "only if excess
consumption is established".

       45.6 In Section 5.4, in the fourth line, after 'planned' insert "design
criteria of the Building" and delete the rest of the sentence.

       45.7 Subject to any limitations imposed by governmental authorities
having jurisdiction thereover and subject to Section 5.4, the Building's
heating, ventilating and air-conditioning systems shall maintain an indoor
temperature of approximately 76 degrees FDB in the summer so long as the Reagan
National Airport outdoor temperature is below 93 degrees FDB and 76 degrees
FWB, and of approximately 70 degrees FDB in the winter so long as the Reagan
National Airport outdoor temperature is above 14 degrees FDB.

       45.8 In Section 5.5, at the end of the paragraph, add: "Landlord shall
provide Tenant with 133 access cards at no initial cost.".

       45.9 In Section 5.7, in the penultimate line, after 'including' insert
"reasonable".


   46. EXTERIOR SIGNAGE

       46.1 Landlord agrees, that Tenant, at its expense, may install one (i)
backlit sign with its name or logo in the same location on the Building as the
current signage provided to Sequent. Such signage shall commence with the Lease
Commencement Date for Tenant's temporary space in Suite 200 at 1420 Spring Hill
Road, and shall be subject to Landlord's reasonable approval and any Fairfax
County or other government approval. Such sign shall be installed and maintained
at Tenant's sole expense. In the event Tenant's occupancy at any time during the
Lease Term becomes less than 18,000 square feet, or Tenant is in monetary
default at any time during the Lease Term, beyond applicable cure periods,
Landlord shall have the right to remove such signage at Tenant's sole expense.


                                       32
<PAGE>   39

   47. USE AND UPKEEP OF PREMISES

       47.1 In Section 6.1, at the end of the paragraph, add: "Landlord
represents that, as of the date hereof, Landlord is not in receipt of any
violation notice regarding laws or codes that affect the Demised Premises or the
Building.".

       47.2 In Section 6.4(a), in the first line, before 'Tenant' insert "Except
for cosmetic changes and decorations,"; and in the fourth line, delete 'or
cosmetic'.

       47.3 In Section 6.4(b), in both the eleventh and twelfth lines, delete
'five (5)' and substitute "ten (10)".

       47.4 In Section 6.4(c), in the third line, delete 'this Lease...and
Tenant' and substitute "the Demised Premises are delivered to Tenant, normal
wear and tear excepted"; in the eighth line, after 'expense' insert "provided
Landlord so advised Tenant when Tenant requested Landlord's consent thereto";
and in the ninth line, after 'date' insert "the Demised Premises are delivered
to Tenant, normal wear and tear excepted." and delete the rest of the sentence.

       47.5 In Section 6.4(d), in the third line, delete 'or of the Building';
in the fourth line, before 'on' insert " specifically and solely"; in the
seventh and eighth lines, delete 'or the Building'; in the ninth line, delete
'of the Building or'; and in the tenth line, delete 'the Building or'.

       47.6 Notwithstanding anything in Section 6.4(d) to the contrary, Landlord
will comply with all final orders of any federal government agency to conform
the common areas of the Building with the requirements of The Americans with
Disabilities Act (ADA). Tenant shall be responsible at its expense for
compliance of the Demised Premises with the ADA.

       47.7 In Section 6.5(a), in the seventh line, before 'acts' insert "the
negligent".

       47.8 In Section 6.5(b), in the first line, before 'reserves' insert ",at
its sole cost',; in the third line, after 'install' insert ",after reasonable
notice,"; in the thirteenth line, before 'None' insert "Landlord shall attempt
to perform all such work during nonbusiness hours and to otherwise minimize the
interference to Tenant's business in the Demised Premises."; and in the last
line, after 'aforesaid' insert ";provided, however, if the Demised Premises are
rendered untenantable thereby for five (5) consecutive business days due to
Landlord's negligence or willful misconduct, then Tenant may abate paying Base
Annual Rent from said fifth (5th) day until the Demised Premises are again
tenantable".

       47.9 In Section 6.6, in the second line, after 'Building' insert "except
as provided hereinafter,"; in the fourth line, before 'approve' insert
"reasonably"; in the fifth line, before 'opinion' insert "reasonable"; and in
the last line, after '(1)' insert "business".

       47.10 In Section 6.9, in the ninth line, delete 'three (3)' and
substitute "ten (10)", and delete 'to' and substitute "is received by"; and at
the end of the Section insert "Landlord shall use reasonable efforts to enforce
the Rules and Regulations equitably.".

       47.11 In Section 6.11, in the last line, after 'default' insert ", beyond
any applicable notice and cure period,".

       47.12 In Section 6.12, in the second line, delete 'necessary' and
substitute "critical".


   48. ACCESS

       48.1 In Section 7.1, in the second line, after 'times' insert "after
reasonable notice (except in emergencies)"; and in the third line, after
'necessary' insert ", provided Landlord shall endeavor to make such repairs
during nonbusiness hours and otherwise minimize interference with Tenant's
business on the Premises".


                                       33
<PAGE>   40
                48.2    Provided Tenant is not then in default of any of the
terms or conditions of this Lease, Landlord's access to the Demised Premises
shall be subject to Tenant's security regulations and made upon reasonable
notice, except if such access is required for emergency purposes or for the
purposes set forth in clauses (a) and (c) of Section 7.1.

                48.3    Subject to the conditions set forth in Section 7.2,
Tenant may install additional locks or security equipment in the Demised
Premises as required for compliance with government security regulations.

                48.4    In Section 7.3, in the tenth line, after `advisable'
insert ", provided Tenant's access to the Demised Premises shall not be
materially impaired".


        49.     LIABILITY

                49.1    In Section 8.1, in the third line, after `Property'
insert "; provided, however, the foregoing provision shall not apply (a) if the
loss was caused by the negligence of Landlord, Landlord's Agent or their agents
or employees, and (b) the Tenant has not otherwise waived and released its
claims pursuant to Section 8.5(f)." and delete the remainder of the paragraph.

                49.2    In Section 8.2, in the sixth line, after the first
`Tenant' insert a period and delete the remainder of the paragraph.

                49.3    In Section 8.4, at the beginning of the paragraph,
insert "Subject to Tenant's right of quiet enjoyment,".

                49.4    Nothing contained in Section 8 shall be construed to
require Tenant to indemnify and hold harmless Landlord, its agents or employees,
from Landlord's liability to third parties for Landlord's negligent acts or
omissions or willful misconduct.


        50.     DAMAGE

                50.1    In Section 9.1, in the second line, before `acts' insert
"negligent".

                50.2    In Section 9.2, in the second line, before `acts' insert
"negligent"; and delete the penultimate sentence entirely.

                50.3    In Section 9.3(a)(i), in the second line, before `acts'
insert "negligent".

                50.4    In Section 9.3(a)(ii)(l), in the second line, before
`acts' insert "negligent".

                50.5    In Section 9.3(a)(ii)(2), in the eleventh line, delete
`ten (10)' and substitute "thirty (30)".


        51.     CONDEMNATION

                51.1    In Section 10.1, in the twelfth line, before `operated'
insert "reasonably".











                                       34


<PAGE>   41


        52.     DEFAULTS AND REMEDIES

                52.1    Notwithstanding anything to the contrary in Sections
12.1 and 12.2, if Tenant defaults in the payment of Base Annual Rent, Additional
Rent or any other sum required to be paid by Tenant, or if Tenant defaults in
the performance of or compliance with any other covenant, condition, agreement,
rule or regulation herein contained, Landlord shall give Tenant written notice
of such default. If Tenant fails to cure any default in the payment of Base
Annual Rent, Additional Rent or any other sum required to be paid by Tenant
within ten (10) days after the effective date of such notice, or fails to cure
any other default within thirty (30) days after the effective date of such
notice (or if such other default is of such nature that it cannot be completely
cured within said thirty (30) days, if Tenant fails to commence to cure within
said thirty (30) days and thereafter proceed with reasonable diligence and in
good faith to complete the cure), then Landlord shall be entitled to all rights
and remedies available to Landlord pursuant to Section 12 in the event of
Tenant's default. Nevertheless, in the event Tenant defaults in the payment of
Base Annual Rent, Additional Rent or any other sum required to be paid by Tenant
or if Tenant otherwise defaults in the performance of or compliance with any
other covenant, condition, agreement, rule or regulation herein contained, two
(2) times in any twelve (12) month period, Landlord shall not be required during
such twelve (12) month period to send notice of any default hereunder before
proceeding with its remedies under Section 12. Tenant acknowledges that the
purpose of the preceding sentence is to prevent repetitive defaults by Tenant
under this Lease, which work a hardship upon Landlord and deprive Landlord of
the timely performance by Tenant of its obligations hereunder this Lease.

                52.2    In Section 12.9(a), delete the first three (3) sentences
entirely.

                52.3    Sections 12.9(b) and (c) are deleted entirely.

                52.4    Section 12.13 is deleted entirely.


        53.     SUBORDINATION

                53.1    In Section 13.1, in the sixth line, before `Landlord's'
insert "receipt of"; and in each of the sixth and ninth lines, delete `ten (10)'
and substitute "twenty (20)".

                53.2    In Section 13.2, in both the first line and last
sentence, delete `ten (10)' and substitute "twenty (20)"; in each of the fourth,
seventh, and ninth lines, after `that' insert ", to Tenant's knowledge,".

                53.3    In Section 13.4(a), in the first line, before `comply'
insert "but not exceeding an incidental amount,"; in the fourth line, delete
both `unreasonably' and `materially' and substitute "more than incidentally"; in
the eleventh line, delete `be in material derogation or diminution of' and
substitute "more than incidentally derogate or diminish"; and in the last line,
delete `materially' and substitute "more than incidentally".

                53.4    Notwithstanding anything to the contrary in Section 13,
Landlord agrees to use reasonable efforts to obtain a nondisturbance agreement
from existing or future mortgagees and any trustee named or secured by a
mortgage, and from any existing or future ground lessor, granting unto Tenant,
as long as Tenant is not in default beyond any applicable cure period under this
Lease, the right to continue peacefully in possession of the Demised Premises in
the event of foreclosure under any existing or future mortgage or deed of trust,
sale at foreclosure, acceptance of any deed in lieu of foreclosure or
termination of any existing or future ground lease. Such agreement shall be
contingent upon Tenant's agreement to attorn to and recognize any purchaser at
any foreclosure sale, any party taking by deed in lieu of foreclosure, any
subsequent ground lessor, and their successors and assigns, as the
successor-in-interest to Landlord in the event of foreclosure, sale at
foreclosure, acceptance of deed in lieu of foreclosure or termination or
transfer of such ground lease.

                                       35
<PAGE>   42



        54.     TENANT'S HOLDOVER


                54.1    In Section 14.2, in the third line, delete `three' and
substitute "one and one-half"; and in the fifth line, before `loss' insert
"direct" and delete `,direct and consequential,'.


        55.     SECURITY DEPOSIT

                55.1    In Section 15, in the second line, after `default'
insert ", beyond any applicable cure period,".

                55.2    Notwithstanding anything to the contrary in Section 15
of the Lease, the amount stipulated in Section 1.6 of this Lease as a security
deposit, at Tenant's option, may be in the form of an irrevocable and
unconditional letter of credit from a Washington, D.C., area bank, in a form
reasonably acceptable to Landlord. If the letter of credit would expire during
the Lease Term, Tenant shall replace the letter of credit at least thirty (30)
days prior to its expiration. If Tenant has not, at least thirty (30) days prior
to the expiration of the letter of credit, delivered a replacement letter of
credit having an expiration date at least six months later, Landlord may convert
any letter of credit then held by Landlord into a cash deposit in the full
amount thereof. If Tenant is in default beyond any cure period or if the
pre-conditions set forth in Section 15 are not met, then the letter of credit
shall be converted into a cash deposit and applied to sums due Landlord. If
Tenant is not in default beyond any cure period and the pre-conditions set forth
in Section 15 are met, any letter of credit then held by Landlord shall be
cancelled within thirty (30) days after the expiration or earlier termination of
this Lease. Notwithstanding anything to the contrary, provided Tenant has not
been in monetary default beyond the applicable cure period during the previous
twelve month period, the Security Deposit shall be reduced in accordance with
the following schedule:

<TABLE>
<CAPTION>

                          Reduction Amount            Balance Remaining
                          ------------------------------------------------
<S>                         <C>                       <C>
Lease Execution                --------                  $700,000.00
End of First Lease Year        $      0.00               $700,000.00
End of Second Lease Year       $      0.00               $700,000.00
End of Third Lease Year        $210,000.00               $490,000.00
End of Fourth Lease Year       $ 70,000.00               $420,000.00
End of Fifth Lease Year        $ 70,000.00               $350,000.00
End of Sixth Lease Year        $      0.00               $350,000.00
End of Seventh Lease Year      $      0.00               $350,000.00
End of Eighth Lease Year       $116,000.00               $234,000.00
End of Ninth Lease Year        $116,000.00               $1l8.000.00
End of Tenth Lease Year        $      0.00               $118,000.00
</TABLE>


        56.     QUIET ENJOYMENT

                56.1    In Section 16, in the last line, delete the period and
insert ", provided Landlord has attempted to perform such work after business
hours and otherwise minimize the interference to Tenant's business on the
Premises.".


        57.     WAIVER OF JURY TRIAL

                57.1    In Section 18, in the last line, delete `and/or
Landlord's principal place of business'.


        58.     LIMITATION OF LANDLORD'S LIABILITY; NOTICE

                58.1    Section 19.1 is deleted entirely.


                                  36

<PAGE>   43
         59. TENANT'S RESPONSIBILITY REGARDING HAZARDOUS SUBSTANCES

             59.1 In Section 21.2(b), in the last line, after 'Laws' insert ";
except that Tenant may use and store, in accordance with Law, reasonable
quantities of substances commonly used in office buildings, e.g., cleaning
supplies".

             59.2 In Section 21.4, in the third line, after 'including' insert
"reasonable".

             59.3  At the end of Section 21, add the following:

LANDLORD'S REPRESENTATION. Landlord represents that, as of the date hereof,
Landlord is not in receipt of any violation notice regarding Hazardous
Substances that affects the Demised Premises or the Building.


         60. TENANT FORCE MAJEURE

             60.1 If Tenant is in any way delayed or prevented from performing
any non-monetary obligation due to fire, act of God, governmental act or failure
to act, labor dispute, inability to procure materials or any cause beyond
Tenant's reasonable control (whether similar or dissimilar to the foregoing
named events) (financial inability excepted), then the time for performance of
such obligation shall be excused for the period of such delay or prevention and
extended for a period equal to the period of such delay or prevention; provided,
that this Section shall not excuse Tenant from the prompt payment of any Base
Annual Rent, Additional Rent or any other charges payable by Tenant hereunder.


         61. RECORDATION

             61.1  In Section 32, in the second line, before 'attorneys" insert
"reasonable".


         62. TIME OF ESSENCE

             62.1  Section 33 is hereby deleted.


         63. BROKERS AND COMMISSIONS

             63.1  Section 34 is hereby deleted in its entirety and the
following is substituted therefor:

             "Landlord and Tenant each hereby represents and warrants that, in
connection with this Lease, each did not retain, consult or deal with any broker
or real estate agent, salesperson or finder (other than Landlord's Agent), and
there is no commission, charge, or other compensation due on account thereof in
regard thereto, excepting only Insignia/ESG and Charles E. Smith Real Estate
Services L.P., both of whose commissions are the responsibility of Landlord.
Each party hereto shall indemnify and hold harmless the other (and Tenant shall
also indemnify and hold harmless Landlord's Agent) against and from any claims
for brokerage or other commissions by reason of a breach of the indemnifying
party's foregoing representation and warranty. Tenant shall pay, or upon demand
reimburse Landlord and Landlord's Agent for, all costs and expenses, including
attorneys' fees, necessary to remove from record any lien filed against the
rents payable pursuant to this Lease and/or against the Demised Premises and/or
the Building, by reason of a breach by Tenant of the foregoing representation
and warranty. The rights, obligations, warranties and representations in this
Section shall survive the expiration or sooner termination of the Lease Term.".






                                       37
<PAGE>   44




         64. EXHIBIT C

             64.1 In Paragraph 4, in the second line, before 'approved' insert
"reasonably".

             64.2 In Paragraph 5, in the penultimate line, before 'rubbish'
insert "its".

             64.3 In Paragraph 7, in the first line, after 'Lease,' insert "
except for normal office wall hangings,".


         65. RIGHT OF FIRST OFFERING

             65.1 If before the last twelve (12) months of the Lease Term, the
existing tenant(s) occupying space contiguous to the Demised Premises on the
Third (3rd) floor of the Building (a) elect(s) to vacate such space and its
(their) lease agreement(s) is (are) terminated, or (b) do(es) not enter into a
new lease agreement or (c) do(es) not exercise any extension or renewal rights
under its (their) existing lease(s), and (d) no other tenant(s) in the Building
shall have previously been granted an option or prior right of first offering on
such block of contiguous space, and such block of contiguous space thereby
becomes available, then within a reasonable period of time after Landlord is
notified by the existing tenant occupying such block of contiguous space that
such block of space will become available, Landlord shall first offer the entire
block of contiguous space to Tenant in writing at the fair market base annual
rent and additional rent in effect at the time such space becomes available, and
on such other terms and conditions as are reasonably acceptable to Landlord.
Tenant shall have ten (10) days in which to accept in writing Landlord's offer
for the entire block of contiguous space, time being of the essence. If Tenant
fails to accept Landlord's offer within the time specified, Landlord shall have
no further obligation to Tenant with respect to any of such space. In the event
Tenant accepts Landlord's offer for the entire block of contiguous space within
the time specified, Tenant agrees to accept the space in its "as is" condition
at the time the previous occupant vacates and shall be obligated for the payment
of base annual rent and additional rent from the date following the day such
space is vacated, regardless of any time required to construct, alter or
redecorate the space to Tenant's requirements. Tenant shall execute an amendment
to this Lease evidencing the terms and conditions for the leasing of this
additional space. Landlord makes no representation that any carpeting or special
improvements present in the additional space prior to the time the previous
occupant vacates the space will remain for Tenant's use. This right of first
offering shall not apply to any block of space which is offered for sublet or
assignment by the existing tenant thereof, nor shall it apply to any block of
space re-leased by the existing tenant thereof by renewal, extension or
renegotiation. This right of first offering is contingent on Tenant not having
been in default beyond any cure period of any of the terms or conditions of this
Lease at any time during the twelve month period before Landlord's offer,
Tenant's acceptance of Landlord's offer and thereafter through the date on which
the term of the additional space commences, and is further contingent on Tenant
being in substantial (51% or more) occupancy of the Demised Premises at each
such point in time. Notwithstanding the foregoing, Landlord shall have no
liability whatsoever for failing to notify or advise Tenant of the availability
of any space pursuant to this provision and Tenant hereby waives all legal and
equitable rights with respect hereto.


         66. EXECUTION OF DOCUMENT

             66.1 In the event Tenant does not execute and return this document
by the close of business on September 20, 2000, then Landlord may market the
subject space to others without further notice to Tenant.





                                       38
<PAGE>   45



                                    EXHIBIT C

                         BUILDING RULES AND REGULATIONS


 1.  Tenant shall not obstruct or interfere with the rights of other tenants of
     the Building or the Complex, or of persons having business in the Building
     or the Complex, or in any way injure or annoy such tenants or persons.
     Tenant will not conduct any activity within the Demised Premises which will
     create excessive traffic or noise anywhere in the Building or the Complex.
     Tenant shall not bring or keep within the Building any animal, bicycle,
     motorcycle, or type of vehicle except as required by law.

 2.  Tenant shall promptly report to Landlord's Agent all accidents and
     incidents occurring on or about the Demised Premises, the Building and/or
     the Complex which involve or relate to the security and safety of persons
     and/or property.

 3.  Tenant shall use and occupy the Demised Premises only for the purposes
     specified in Section 1.8 of the Lease and for no other purpose whatsoever,
     and shall comply, and cause its employees, agents, contractors, invitees
     and other users of the Demised Premises to comply, with applicable zoning
     and other municipal regulations, including but not limited to smoking
     regulations. Canvassing, soliciting and peddling in the Building or
     anywhere in the Complex are prohibited, and Tenant shall cooperate to
     prevent such activities.

 4.  All office equipment and any other device of any electrical or mechanical
     nature shall be placed by Tenant in the Demised Premises in settings
     approved by Landlord, so as to absorb or prevent any vibration, noise, or
     annoyance. Tenant shall not construct, maintain, use or operate within the
     Demised Premises or elsewhere in the Building or outside of the Building
     any equipment or machinery which produces music, sound or noise, which is
     audible beyond the Demised Premises. Tenant shall not cause objectionable
     noises, vibrations or odors within the Building.

 5.  Tenant shall not deposit any trash, refuse, cigarettes, or other substances
     of any kind within or out of the Building, except in the refuse containers
     provided therefor. No material shall be placed in the trash boxes or
     receptacles if such material is of such nature that it may not be disposed
     of in the ordinary and customary manner of removing and disposing of office
     building trash and garbage without being in violation of the Lease or any
     law or ordinance governing such disposal. Tenant shall be charged the cost
     of removal for any items left by Tenant that cannot be so removed. All
     garbage and refuse disposal shall be made only through entry ways and
     elevators provided for such purposes and at such times as Landlord shall
     designate. Tenant shall not introduce into the Building any substance which
     might add an undue burden to the cleaning or maintenance of the Demised
     Premises or the Building. Tenant shall exercise its best efforts to keep
     the sidewalks, entrances, passages, courts, lobby areas, garages or parking
     areas, elevators, escalators, stairways, vestibules, public corridors and
     halls in and about the Building (hereinafter "Common Areas") clean and free
     from rubbish. Tenant shall not cause any unnecessary labor by reason of
     Tenant's carelessness or indifference in the preservation of good order and
     cleanliness.

 6.  Tenant shall use the Common Areas only as a means of ingress and egress,
     and Tenant shall permit no loitering by Tenant's agents, employees,
     visitors or invitees upon Common Areas or elsewhere within the Building.
     Tenant shall comply, and cause its employees, agents, contractors, invitees
     and other users of the Demised Premises to comply, with all rules and
     regulations adopted by Landlord governing the use of the Common Areas. The
     Common Areas and roof of the Building are not for the use of the general
     public, and Landlord shall in all cases retain the right to control or
     prevent access thereto by all persons whose presence, in the judgment of
     Landlord, shall be prejudicial to the safety, character, reputation or
     interests of the Building and its tenants. Tenant shall not enter or
     install equipment in the mechanical rooms, air conditioning rooms,
     electrical closets, janitorial closets, or similar areas or go upon the
     roof of the Building without the prior written consent of Landlord. Tenant
     shall not install any radio or television antenna, loudspeaker, or other
     device on the roof or exterior walls of the Building. Tenant shall not, nor
     shall Tenant's agents, employees or contractors, enter or install equipment
     in or at the equipment room(s) or closet(s), inside telecommunications
     and/or data transmission wire space and/or conduits or the telephone wire
     demarcation point in the Building without Landlord's prior consent.

 7.  Without limitation upon any of the provisions of the Lease, Tenant shall
     not mark, paint, drill into, cut, string wires within, or in any way deface
     any part of the Building, without the prior written consent of Landlord,
     and as Landlord may direct. Upon removal of any wall decorations or
     installations or floor coverings by Tenant, any damage to the walls or
     floors shall be repaired by Tenant at Tenant's sole cost and expense.
     Tenant shall not lay linoleum or similar floor coverings so that the same
     shall come into direct contact with the floor of the Demised Premises and,
     if linoleum or other similar floor covering is to be used, an interlining
     of builder's deadening felt shall be first affixed to the floor, by a paste
     or other materials soluble in water. The use of cement or other similar
     adhesive material is expressly prohibited. Floor distribution boxes for
     electric and telephone wires must remain accessible at all times.

 8.  Tenant shall not install or permit the installation of any awnings, shades,
     mylar films or sunfilters on windows. Tenant shall cooperate with Landlord
     in obtaining maximum effectiveness of the cooling system of the Building by
     closing drapes and other window coverings when the sun's rays fall upon
     windows of the Demised Premises. Tenant shall not obstruct, alter or in any
     way impair the efficient operation of the Systems, nor shall Tenant tamper
     with or change the setting of any thermostat or temperature control valves
     in the Building (this is not applicable in VAV buildings). Tenant shall not
     cover induction units.



                                    Exh. C-l
<PAGE>   46
 9.  Tenant shall not use the washrooms, restrooms and plumbing fixtures of the
     Building, and purtenances thereto, for any purpose other than the purpose
     for which they were constructed, and Tenant shall not deposit any
     sweepings, rubbish, rags, or toxic or flammable products, or other improper
     substances, therein. Tenant shall not waste water by interfering or
     tampering with the faucets or otherwise. If Tenant or Tenant's employees,
     agents, contractors, jobbers, licensees, invitees, guests or visitors cause
     any damage to such washrooms, restrooms, plumbing fixtures or
     appurtenances, such damage shall be repaired at Tenant's expense, and
     Landlord shall not be responsible therefor.

10.  Subject to applicable fire or other safety regulations, all doors opening
     onto Common Areas and all doors upon the perimeter of the Demised Premises
     shall be kept closed and, during non-business hours, locked, except when in
     use for ingress or egress. If Tenant uses the Demised Premises after
     regular business hours or on non-business days, Tenant shall lock any
     entrance doors to the Building or to the Demised Premises used by Tenant
     immediately after using such doors. Tenant shall cooperate with energy
     conservation by limiting use of lights to areas occupied during
     non-business hours.

11.  Employees of Landlord shall not receive or carry messages for or to Tenant
     or any other person, nor contract with nor render free or paid services to
     Tenant or Tenant's employees, contractors, jobbers, agents, invitees,
     licensees, guests or visitors. In the event that any of Landlord's
     employees perform any such services, such employees shall be deemed to be
     the agents of Tenant regardless of whether or how payment is arranged for
     such services, and Tenant hereby indemnifies and holds Landlord harmless
     from any and all liability in connection with any such services and any
     associated injury or damage to property or injury or death to persons
     resulting therefrom.

12.  All keys to the exterior doors of the Demised Premises shall be obtained by
     Tenant from Landlord, and Tenant shall pay to Landlord a reasonable deposit
     determined by Landlord from time to time for such keys. Tenant shall not
     make duplicate copies of such keys. Tenant shall, upon the termination of
     its tenancy, provide Landlord with the combinations to all combination
     locks on safes, safe cabinets, and other key-controlled mechanisms therein,
     whether or not such keys were furnished to Tenant by Landlord. In the event
     of the loss of any key furnished to Tenant by Landlord, Tenant shall pay to
     Landlord the cost of replacing the same or of changing the lock or locks
     opened by such lost key if Landlord shall deem it necessary to make such a
     change. The word "key" as used herein shall refer to keys, keycards, and
     all such means of obtaining access through restricted access systems.

13.  No signs, advertisements or notes shall be painted or affixed on or to any
     windows, doors or other parts of the Building visible from the exterior
     (other than as expressly permitted by the terms of the Lease), or to any
     Common Area or public area of the Building.

14.  Landlord will provide and maintain a directory board for the Building, in
     the main lobby of the Building, and no other directories shall be allowed.

15.  All contractors, contractors' representatives and installation technicians
     tendering any service to Tenant shall be referred by Tenant to Landlord for
     Landlord's supervision, approval and control before the performance of any
     contractual service. This provision shall apply to all work performed in
     the Building.

16.  After initial occupancy, movement in or out of the Building of furniture or
     office equipment, or dispatch or receipt by Tenant of any bulky material,
     merchandise or material which requires use of elevators shall be restricted
     to the use of freight elevators only. Absolutely no carts or dollies are
     allowed through the main entrances or on passenger elevators. All items not
     hand carried must be delivered via the appropriate loading dock and freight
     elevator, if any.

17.  No portion of the Demised Premises shall at any time be used or occupied as
     sleeping or lodging quarters.

18.  Landlord shall have the power to prescribe the weight and position of safes
     and other heavy equipment, which shall in all cases, to distribute weight,
     stand on supporting devices approved by Landlord. All damages done to the
     Building by taking in or putting out any property of Tenant, or done by
     Tenant's Property while in the Building, shall be repaired at the expense
     of Tenant.

19.  For purposes hereof, the terms "Landlord", "Landlord's Agent", "Tenant",
     "Complex", "Building", "Demised Premises", "Tenant's Property" and
     "Systems" are defined in the Lease to which these rules and regulations are
     attached. Wherever these terms appear in the rules and regulations they
     shall have the same meaning as defined in the Lease.

20.  These Rules and Regulations are in addition to, and shall not be construed
     to in any way modify or amend, in whole or in part, the agreements,
     covenants, conditions and provisions of any lease of any premises in the
     Building.



                                    Exh. C-2
<PAGE>   47




                                   EXHIBIT "D"
                      MINIMUM CLEANING SERVICES BY LANDLORD

A.    DAILY -    Monday through Friday, except legal holidays.

      1.   Empty waste baskets, clean ashtrays.

      2.   Dust accessible areas of desk tops.

      3.   Vacuum carpet in all areas of the Demised Premises.

      4.   Mop spillages on tile floors.

      5.   Clean lavatories and replace supplies.

      6.   Dust and mop kitchens within the Demised Premises, provided that
           Tenant shall be responsible for the cleaning of any dishes, glasses
           or utensils in the kitchen areas. Tenant shall maintain any coffee
           pots and utensils located in the Demised Premises.

B.    WEEKLY

      1.   Dust accessible areas of furniture, convectors and other furnishings.

      2.   Clean glass in doors and partitions.


 C.   MONTHLY

      1.   Mop and buff tile floors,

      2.   Dust venetian blinds, window frames and exterior of lighting
           fixtures.

      3.   Spot clean walls.

      4.   Clean telephones.


 D.   QUARTERLY

      1.   Clean and refinish tile floors where necessary.

      2.   Clean baseboards.


 E.   SEMI-ANNUALLY

      1.   Wash windows.

 F.   ANNUALLY

      1.   Wash light fixtures and lenses.

      2.   Clean venetian blinds.


 NOTE:     Cleaners will not move papers or other materials from surfaces to be
           cleaned, dusted or vacuumed. Trash not in wastebaskets should be
           clearly marked "TRASH". Cleaning of private kitchens and baths is the
           responsibility of the Tenant.


<PAGE>   48


                                    EXHIBIT E

                                    GUARANTY

            FOR VALUE RECEIVED, in consideration for, and as an inducement to
CESC TYSONS DULLES PLAZA L.L.C. ("Landlord") for entering into that Lease with
NET 2000 COMMUNICATIONS REAL ESTATE, INC. ("Tenant") for Suites 400 and 410 in
Tysons Dulles Plaza II of even date herewith, the undersigned Guarantor does
hereby unconditionally and without reservation, personally guarantee to Landlord
that Tenant shall promptly and faithfully perform and fulfill all of the
obligations, covenants and agreements in said Lease on the part of Tenant to be
performed and fulfilled; and further, if Tenant shall default in the payment of
Base Annual Rent, Additional Rent or any other charges to be paid by Tenant
pursuant to the Lease, or in the performance of any of the other obligations,
covenants or agreements to be performed by Tenant pursuant to the Lease, the
undersigned Guarantor shall well and truly pay said Base Annual Rent, Additional
Rent and any other charges to be paid by Tenant pursuant to the Lease, and all
arrears thereof, and shall well and truly perform, or cause to be performed, all
of the other obligations, covenants and agreements to be performed by Tenant
pursuant to the Lease, and shall well and truly pay all damages, claims,
demands, costs and expenses which Landlord may suffer or sustain or which may
arise in consequence of the breach or nonperformance by Tenant of any of its
obligations, covenants and agreements under said Lease.

            The undersigned hereby expressly waives any and all notice of any
breach or default by Tenant under said Lease and does hereby consent to any
extensions or indulgences that may hereafter be given to Tenant by Landlord. The
undersigned Guarantor further agrees that the failure of Landlord to require
strict performance at any time of any of the terms and provisions of said Lease,
and/or the waiver of performance by Landlord, shall not release the undersigned
Guarantor from liability under this Guaranty, and that the terms and provisions
of said Lease may be altered or modified (other than by increasing the amount of
Base Annual Rent, Additional Rent and any other charges to be paid by Tenant
pursuant to the Lease) without notice to Guarantor and without Guarantor's
consent, approval or waiver and without releasing the Guarantor from any
liability under this Guaranty.

            Guarantor hereby waives all legal and equitable rights it has, or
may have, against Tenant arising out of Guarantor's liability to Landlord under
this Guaranty and/or Guarantor's payment under this Guaranty, including, without
limitation, all rights of indemnification, contribution and subrogation, all to
the effect that Guarantor shall not, by virtue of this Guaranty or payment
hereunder, be deemed a creditor of Tenant. Guarantor agrees that in the event of
any default by Tenant under the Lease, Landlord may enforce this Guaranty
without first exhausting its remedies against Tenant.

            The person executing this Guaranty hereby represents and warrants
that this Guaranty is enforceable in accordance with its terms, that all
corporate, partnership and other legal action (if applicable) has been taken by
the directors, shareholders, partners or owners of Guarantor to authorize the
execution of this Guaranty and that the person executing this Guaranty has full
power and authority to do so.


ATTEST:                             GUARANTOR: NET 2000 COMMUNICATIONS, INC.


                                    BY:                                (SEAL)
-----------------------------           -------------------------------
Corporate Seal      Secretary                Name:
                                             Title:


<PAGE>   49




                                   EXHIBIT "G"


      The "Rentable Area" of the Building and the Demised Premises shall be
determined by Landlord's architect and as used herein shall refer to

      (a) in the case of a single tenancy floor, all floor area measured from
the inside dominant surface of the opposite outer wall excluding outer glass or
finished column wall of the Building to the inside dominant surface of the
opposite outer wall excluding only the areas ("service areas") within the
outside walls which are major vertical penetrations used for building stairs,
fire towers, elevator shafts, flues, vents, stacks, pipe shafts and vertical
ducts but including columns or projections necessary to the Building and any
such service area penetrations under 64 square inches and any such service areas
which are for the specific use of the particular tenant such as special stairs,
dumbwaiters, lifts, or elevators plus any areas exclusively serving only that
floor or tenant, such as elevator lobbies, public corridors, toilets, janitors'
closets, electrical closets, mechanical spaces, telephone closets, etc., plus an
allocation of the square footage of the Building's elevator rooms and main
mechanical and electrical rooms, management office, atriums, the main floor
lobby areas, and other areas necessary to provide customary services to the
Building. And

      (b) in the case of a floor to be occupied by more than one (l) tenant,
all floor areas within the inside dominant surface of the outer glass or
finished column walls enclosing the Demised Premises and measured to the
mid-point of the wall separating areas leased by or held for lease to other
tenants or from areas devoted to corridors, elevator lobbies, rest rooms,
mechanical rooms, janitors' closets, and other similar facilities for the use of
all tenants on the particular floor (hereinafter called "common areas"), but
including a proportionate part of the common areas located on such floor based
upon the ratio which the tenant's Rentable Area (excluding common areas) on such
floor bears to the aggregate Rentable Area (excluding common areas) on such
floor plus an allocation of the square footage of the Building's elevator rooms
and main mechanical and electrical rooms, management office, atriums, the main
floor lobby areas, and other areas necessary to provide customary services to
the Building. No deductions from Rentable Area shall be made for columns or
projections necessary to the Building or for service area penetrations under 64
square inches within the Demised Premises, or for any such service areas which
are for the specific use of the particular tenant such as special stairs,
dumbwaiters, lifts or elevators, or for any areas serving exclusively that
tenant, such as toilets, janitors' closets, electrical closets, mechanical
spaces, telephone closets, etc.