<PAGE>

                                                                    EXHIBIT 10.1

                                   L E A S E
                                   ---------



THIS INSTRUMENT IS A LEASE, dated as of August 31, 1995 in which the Landlord
and the Tenant are the parties hereinafter named, and which relates to space in
the building (the "Building") known and numbered as 80 Blanchard Road,
Burlington,  Massachusetts. The parties to this instrument hereby agree with
each other as follows:

                                   ARTICLE I
                                   ---------

                             BASIC LEASE PROVISIONS
                             ----------------------

      1.1   INTRODUCTION. The following terms and provisions set forth basic
            --------------                                                  
      data and, where appropriate, constitute definitions of the terms
      hereinafter listed:

      1.2   BASIC DATA.
            -----------

      LANDLORD: Teachers Realty Corporation

      LANDLORD'S ORIGINAL ADDRESS:
         c/o Finard & Company, Inc.
         Three Burlington Woods Drive
         Burlington, MA 01803

TENANT:  Desktop Data, Inc.
 
      TENANT'S ORIGINAL ADDRESS:
         1601 Trapelo Road
         Waltham, MA 02154
 
      GUARANTOR: N/A
 
      BASIC RENT:

                                      -1-
<PAGE>
 
<TABLE> 
<CAPTION>  
            Period or                Rate Per    Basic Rent     Monthly
            Lease Year              Square Foot  (per annum)   ----------
----------------------------------  -----------  -----------
<S>                                 <C>          <C>           <C>
                1                        $10.03  $302,735.49   $25,227.95
 
                2                        $10.28  $310,281.24   $25,856.77
 
                3                        $10.53  $317,826.99   $26,485.58
 
                4                        $10.78  $325,372.74   $27,114.39
 
                5                        $11.03  $332,918.49   $27,743.20
 
                6                        $11.03  $332,918.49   $27,743.20
 
                7                        $11.03  $332,918.49   $27,743.20
 
                8                        $11.03  $332,918.49   $27,743.20
          (partial year)
</TABLE>

      The Basic Rent set forth above is subject to increase and adjustment
      effective as of the First Expansion Commencement Date by the amount of the
      First Expansion Rent and again on the Second Expansion Commencement Date
      by the amount of the Second Expansion Rent due to the addition of the
      First Expansion Space and the Second Expansion Space to the "Premises",
      all as more particularly set forth in Section 14.29(c) and (d) of this
      Lease.  Notwithstanding the foregoing to the contrary, in the event that
      the entire Expansion Space is added to the Premises as of the "Expansion
      Commencement Date", pursuant to Section 14.29(b) hereof (rather than
      phased in pursuant to Sections 14.29(c) and (d) hereof) then, effective as
      of the Expansion Commencement Date, the Basic Rent specified above shall
      be increased and adjusted by the "Expansion Rent" (as defined in Section
      14.29(b) hereof).
 
      PREMISES RENTABLE AREA:

                                      -2-
<PAGE>
 
Period                                          Premises Rentable Area
-------------------------------------  -----------------------------------------
 
A.  Subject to D. hereof,              Approximately 30,183 rentable square feet
 Commencement Date through the day
 immediately preceding the First
 Expansion Commencement Date
 
B.  Subject to D. hereof, First        Approximately 36,238 rentable square feet
 Expansion Commencement Date through
 the day immediately preceding the
 Second Expansion Commencement Date
 
C.  Subject to D. hereof, Second       Approximately 39,482 rentable square feet
 Expansion Commencement Date through
 the last day of the Term of this
 Lease

         D.  Notwithstanding the foregoing to the contrary, in the event that
         the entire Expansion Space is added to the Premises as of the Expansion
         Commencement Date pursuant to Section 14.29(b) hereof (rather than
         phased in pursuant to Sections 14.29(c) and (d) hereof) then, effective
         as of the Expansion Commencement Date and thereafter for the remainder
         of the Term of this Lease, the Premises Rentable Area shall be deemed
         to be 39,482 rentable square feet.

      PERMITTED USES: General office and uses that are ancillary and incidental
      to general office use exclusive however of any office use which would
      cause the Premises to be deemed a "Place of Public Accommodation" as
      defined in the Americans with Disabilities Act of 1990 and any regulations
      promulgated thereunder, all as amended.

      ESCALATION FACTOR:

                                      -3-
<PAGE>
 
Period                                    Escalation Factor
----------------------------------------  ------------------
A.  Subject to D. hereof, Commencement          76.45%
 Date through the day immediately               
 preceding the First Expansion                  
 Commencement Date                              
                                                
B.  Subject to D. hereof, First                 91.78%
 Expansion Commencement Date through            
 the day immediately preceding the              
 Second Expansion Commencement Date             
                                                
C.  Subject to D. hereof, Second                  100%
 Expansion Commencement Date through
 the last day of the Term of this Lease

         D. Notwithstanding the foregoing to the contrary, in the event that the
         entire Expansion Space is added to the Premises as of the Expansion
         Commencement Date pursuant to Section 14.29(b) hereof (rather than
         phased in pursuant to Section 14.29(c) and (d) hereof) then, effective
         as of the Expansion Commencement Date and thereafter for the remainder
         of the Term of this Lease, the Escalation Factor shall be 100%.

      INITIAL TERM:  7 years and three full calendar months commencing on the
      Commencement Date and expiring at the close of the day which is 87 full
      calendar months after the Commencement Date (plus any partial calendar
      month in which the Commencement Date shall occur in the event that the
      Commencement Date shall be other than the first day of a calendar month).

      SECURITY DEPOSIT:  $229,000.00 payable as and when provided in Section
      14.17 hereof.

      BASE OPERATING EXPENSES: The Operating Expenses for the calendar year
      ending December 31, 1996 adjusted and extrapolated as provided in Section
      9.1(ii) hereof.

      BASE TAXES: The real estate taxes assessed to the Property for the fiscal
      year ending June 30, 1996, as they may be reduced by the amount of any
      abatement.

1.3   ADDITIONAL DEFINITIONS.
      -----------------------

      MANAGER:  Finard & Company, Inc.

                                      -4-
<PAGE>
 
      BUILDING RENTABLE AREA:  39,482 rentable square feet.

      BUSINESS DAYS: All days except Saturday, Sunday, New Year's Day,
      Washington's Birthday, Good Friday, Memorial Day, Independence Day, Labor
      Day, Thanksgiving Day, the Friday immediately following Thanksgiving Day,
      Christmas Day (and the following day when any such day occurs on Sunday).

      COMMENCEMENT DATE: As defined in Section 4.1.

      DEFAULT OF TENANT: As defined in Section 13.1.

      ESCALATION CHARGES: The amounts prescribed in Sections 8.1 and 9.2.

      ESCALATION FACTOR COMPUTATION: Premises Rentable Area divided by the
      Building Rentable Area.

      FORCE MAJEURE: Collectively and individually, strike or other labor
      trouble, fire or other casualty, governmental preemption of priorities or
      other controls in connection with a national or other public emergency or
      shortages of, or inability to obtain, fuel, supplies or labor resulting
      therefrom, or any other cause, whether similar or dissimilar, beyond
      Landlord's reasonable control.

      INITIAL PUBLIC LIABILITY INSURANCE: $1,000,000 per person; $3,000,000 per
      occurrence (combined single limit) for property damage, bodily injury or
      death.

       LEASE YEAR OR LEASE YEAR:   Each consecutive 12 calendar month period
       immediately following the Commencement Date, but if the Commencement Date
       shall fall on other than the first day of a calendar month, then such
       term shall mean each consecutive twelve calendar month period commencing
       with the first day of the first full calendar month of the Initial Term.
       The first lease year shall include any partial month between the
       Commencement Date and the first day of the first full calendar month
       immediately following the Commencement Date.

       OBS Costs:  Shall mean, as to the initial 30,183 square foot Premises
       being built-out pursuant to Article IV hereof, all costs associated with
       completing Landlord's Work resulting from the inclusion of matters not
       shown on Exhibit B into Proposed Plans or Tenant's Plans and those costs
       to Landlord resulting from changes in Tenant's Plans once approved by
       Landlord and Tenant and as to the Expansion Space all costs of performing
       Landlord's Expansion Work, Landlord's First Expansion Work and Landlord's
       Second Expansion Work, as applicable, in excess of, respectively, the
       Expansion Allowance, the 

                                      -5-
<PAGE>
 
       First Expansion Allowance and the Second Expansion Allowance in excess of
       Sections 14.29(b), (c) and (d) of this Lease.

      OPERATING EXPENSES: As set forth in Section 9. 1.

      OPERATING YEAR: As defined in Section 9.1.

      PREMISES:

Period                                            Premises
---------------------------  ---------------------------------------------------
 
A.  Subject to D. hereof,    The portions of the Building marked on Exhibit A
 Commencement Date through   as the "Original Space"
 the day immediately
 preceding the First
 Expansion Commencement
 Date
 
B.  Subject to D. hereof,    The portion of the Building marked on Exhibit A as
 First Expansion             the "Original Space" plus the "First Expansion
 Commencement Date through   Space"
 the day immediately
 preceding the Second
 Expansion Commencement
 Date
 
C.  Subject to D. hereof,    The portion of the Building marked on Exhibit A as
 Second Expansion            the "Original Space" plus the "First Expansion
 Commencement Date through   Space and the "Second Expansion Space"
 the last day of the Term
 of this Lease

         D. Notwithstanding the foregoing to the contrary, in the event that the
         entire Expansion Space is included in the Premises as of the Expansion
         Commencement Date pursuant to Section 14.29(b) (rather than phased in
         pursuant to Sections 14.29(c) and (d) hereof) then, effective as of the
         Expansion Commencement Date and thereafter for the remainder of the
         Term of this Lease, the Premises shall include the entire Expansion
         Space.

      PROPERTY: The Building and the land parcels on which it is located
      (including adjacent sidewalks).

      TAX YEAR: As defined in Section 8.1.

      TAXES: As determined in accordance with Section 8. 1.

      TENANTS REMOVABLE PROPERTY: As defined in Section 5.2.

      TERM OF THIS LEASE: The Initial Term and any extension thereof in
      accordance with the provisions hereof.

      UTILITY EXPENSES: As defined in Section 9.1.

                                      -6-
<PAGE>
 
      EXHIBITS: The following Exhibits are annexed to this Lease and
      incorporated herein by this reference:

      Exhibit A -  Plan showing Premises (including "Original Space", "First
                Expansion Space" and "Second Expansion Space")
      Exhibit B -  Space Plan and Specifications
      Exhibit B-1 - Tenant's Additional Work
      Exhibit C -  Landlord's Base Building Work
      Exhibit D -  Janitorial and Cleaning Services to be
                 provided to Premises
      Exhibit E -  Operating Expenses
      Exhibit F -  Plan of the Land Parcel
      Exhibit G -  Rules and Regulations
      Exhibit H -  Tenant's Approved Signage


                                   ARTICLE II
                                   ----------

                        PREMISES AND APPURTENANT RIGHTS.
                        --------------------------------

      2.1  LEASE OF PREMISES. Landlord hereby demises and leases to Tenant for
           ------------------                                                 
      the Term of this Lease and upon the terms and conditions hereinafter set
      forth, and Tenant hereby accepts from Landlord, the Premises upon the
      terms and conditions hereinafter set forth.

      2.2  APPURTENANT RIGHTS AND RESERVATIONS. (a) Tenant shall have, as
           ------------------------------------                          
      appurtenant to the Premises, the non-exclusive right to use, and permit
      its agents, servants, guests, employees and invitees to use in common with
      others, public or common lobbies, hallways, stairways and elevators and
      common walkways and roadways necessary for access to the Building together
      with common parking areas, and if the portion of the Premises on any floor
      includes less than the entire floor, the common toilets, corridors and
      elevator lobby of such floor; but Tenant shall have no other appurtenant
      rights and all such rights shall always be subject to reasonable rules and
      regulations from time to time established by Landlord pursuant to Section
      14.7 and to the right of Landlord to designate and change from time to
      time areas and facilities so to be used.  Landlord shall not grant rights
      to use the parking areas on the Property to tenants or occupants of other
      buildings, it being agreed and understood that the parking areas located
      on the Property are exclusively for the use of tenants and occupants of
      the Building.

      (b) Excepted and excluded from the Premises are the areas above the
      interior surface plane of the ceiling, floor slab, exterior perimeter
      walls and exterior windows, except the inner surfaces thereof, but the
      entry doors (and related glass and finish work) to the Premises are a part
      thereof; and Tenant agrees that Landlord shall have 

                                      -7-
<PAGE>
 
      the right to place in the Premises (but in such manner as to reduce to a
      minimum interference with Tenant's use of the Premises) interior storm
      windows, subcontrol devices (by way of illustration, an electric sub
      panel, etc.), utility lines, pipes, equipment and the like, in, over and
      upon the Premises. Tenant shall install and maintain, as Landlord may
      require, proper access panels in any hung ceilings or walls as may be
      installed by Tenant in the Premises to afford access to any facilities
      above the ceiling or within or behind the walls. Except as otherwise
      expressly provided in this Lease, Landlord shall be responsible for the
      installation, repair and maintenance of such access panels.

      (c) Tenant and any permitted sublessee or permitted assignee of Tenant
      shall have the right in common with other tenants of the Building to have
      identity on the Building Directory Sign.


                                  ARTICLE III
                                  -----------

                                   BASIC RENT
                                   ----------


      3.1  PAYMENT. (a) Tenant agrees to pay to Landlord, or as directed by
           --------                                                        
      Landlord, commencing on the Commencement Date without offset, abatement
      (except as otherwise expressly provided in this Lease), deduction or
      demand, the Basic Rent. Such Basic Rent shall be payable in equal monthly
      installments, in advance, on the first day of each and every calendar
      month during the Term of this Lease, at Landlord's Original Address, or at
      such other place as Landlord shall from time to time designate by notice
      to Tenant, in lawful money of the United States.  In the event that any
      installment of Basic Rent is not paid within ten (10) days after the due
      date thereof, Tenant shall pay, in addition to any Escalation Charges or
      other additional charges due under this Lease, at Landlord's request an
      administrative fee equal to 5% of the overdue payment.

      (b) Basic Rent for any partial month shall be pro-rated on a daily basis,
      and if the first day on which Tenant must pay Basic Rent shall be other
      than the first day of a calendar month, the first payment which Tenant
      shall make to Landlord shall be equal to a proportionate part of the
      monthly installment of Basic Rent for the partial month from the first day
      on which Tenant must pay Basic Rent to the last day of the month in which
      such day occurs, plus the installment of Basic Rent for the succeeding
      calendar month.

      (c) Intentionally Omitted.

                                      -8-
<PAGE>
 
      (d) Notwithstanding anything contained in Section 1.2 or in this Article
      III to the contrary, Tenant shall not be required to pay Basic Rent for
      and with respect to the first two (2) calendar months of the Initial Term.

                                   ARTICLE IV
                                   ----------

                           COMMENCEMENT AND CONDITION
                           --------------------------


     4.1    COMMENCEMENT DATE.  The Commencement Date shall be the last to occur
            ------------------                                                  
     of (i) November 1, 1995 (the "Construction Completion Date"), or (ii) the
     day following the date on which the Premises are "ready for occupancy" as
     provided in Section 4.2. Notwithstanding the foregoing, if Tenant's
     personnel shall occupy all or any part of the Premises for the conduct of
     its business prior to the Commencement Date, such date shall for all
     purposes of this Lease be the Commencement Date.  The Tenant shall, upon
     demand of the Landlord, execute a certificate confirming the Commencement
     Date as it is determined in accordance with the provisions of this Section
     4.1.  Notwithstanding the foregoing to the contrary, Landlord shall permit
     Tenant's agents to have access to the Premises for purposes of performing
     installation of Tenant's wiring and telecommunications systems in
     coordination with Landlord's Contractors.  Tenant shall cause and require
     that its agents and contractors perform such work in compliance with
     Article V and in such a manner as to avoid substantial interference with
     the performance of Landlord's Work, Tenant's Additional Work and Landlord's
     Base Building Work.  From and after the date of such entry, Tenant shall be
     bound by all of the provisions of this Lease except the obligation to pay
     Basic Rent and Escalation Charges.

     4.2            TENANT'S PLANS; APPROVALS; PREPARATION OF THE PREMISES.
                    -------------------------------------------------------

               (a) Attached hereto as Exhibit B is a Space Plan together with
     certain written specifications (hereafter the "Space Plan") depicting
     installations and improvements necessary to prepare the Premises for
     Tenant's occupancy.  Upon execution and delivery of this Lease by Landlord
     and Tenant, Landlord shall cause its architects and engineers to prepare
     final working drawings and specifications reflecting the work and
     improvements shown on Exhibit B (the "Proposed Plans").  Upon completion of
     such Proposed Plans, Landlord shall submit same to Tenant for review and
     approval Tenant shall either approve or reject such Proposed Plans  within
     ten (10) days after receipt from Landlord.  Tenant hereby agrees to approve
     such Proposed Plans provided that they are substantially in compliance with
     those matters set forth in Exhibit B.  Failure of Tenant to object to any
     aspect of such Proposed Plans  within the time and manner provided 

                                      -9-
<PAGE>
 
     above shall be deemed an approval of such Proposed Plans and authorization
     for Landlord to proceed with Landlord's Work in accordance therewith.
     Tenant shall have the right to consult with Landlord's architect for
     purposes of review and approval of Proposed Plans.

               If Tenant shall reject any aspect of such Proposed Plans within
     the time and manner provided above, Landlord shall promptly make such
     revisions to the Proposed Plans as may be necessary so as to bring them
     into substantial compliance with the matters set forth in Exhibit B.
     Tenant shall approve such revised Proposed Plans provided that the matters
     shown thereon are in substantial compliance with those matters set forth in
     Exhibit B.  Tenant shall approve or reject such revised Proposed Plans
     within Ten (10) days after receipt from Landlord.  Failure of Tenant to
     object to any aspect of such revised Proposed Plans within  the time and
     manner herein provided shall be deemed a waiver of such right by Tenant and
     Tenant shall be deemed to have approved such revised Proposed Plans  as
     submitted by Landlord and to have authorized Landlord to proceed with
     Landlord's Work in accordance therewith.  Upon approval of such Proposed
     Plans by both Landlord and Tenant in accordance with the provisions hereof,
     such working drawings and specifications shall be deemed to be Tenant's
     Plans for all purposes under this Lease.

               To the extent that Tenant shall request any changes or
     modifications to the Proposed Plans (other than changes necessary to make
     the Proposed Plans substantially comply with the matters set forth in
     Exhibit B), and provided the Landlord shall approve such changes, which
     approval shall not be unreasonably withheld or delayed, Landlord shall
     promptly make such revisions as requested by Tenant.  Upon completion of
     such revised Proposed Plans, Landlord shall submit same, together with a
     statement from Landlord of the OBS Costs, if any, and the amount of Tenant
     Delays, if any, in completing Landlord's Work as a result of such requested
     changes, to Tenant for Tenant's prompt review and approval.  Tenant shall
     respond to such revisions within Ten (10) days after receipt from Landlord.
     Tenant's failure to respond to any such changes within the Ten (10) day
     period specified above shall be deemed an approval of such revised Proposed
     Plans, acceptance of the applicable OBS Costs and the amount of Tenant
     Delays, if any, and authorization to Landlord to proceed with the work as
     shown on such revised Proposed Plans.  Upon final approval of revised
     Proposed Plans by Landlord and Tenant, Landlord shall proceed with the work
     as shown on such revised Proposed Plans.

               To the extent that Tenant shall request any changes or
     modifications to Tenant's Plans once they are approved by Landlord and
     Tenant or if Tenant shall require modifications to Proposed Plans to
     include matters not specifically shown on Exhibit B (and provided that
     Landlord shall approve such 

                                      -10-
<PAGE>
 
     changes, in accordance with the provisions of this Lease), Tenant shall pay
     the additional cost of completing Landlord's Work as the result of such
     changes to Landlord as OBS Costs hereunder as follows: 50% of OBS Costs
     shall be paid at the time of approval of such change and 50% shall be paid
     on the Commencement Date (or, in either case, at such later time as
     Landlord advises Tenant of the amount of such excess). Tenant shall, if
     requested by Landlord, execute a work letter confirming such excess costs
     prior to the time Landlord shall be required to commence work.

               Landlord shall exercise all reasonable good faith efforts to
     complete the work ("Landlord's Work") necessary to prepare the Premises for
     Tenant's occupancy pursuant to Tenant's Plans and Landlord's Base Building
     Work on or before the Construction Completion Date,  but Tenant shall have
     no claim against Landlord for failure to complete such Landlord's Work and
     Landlord's Base Building Work on or before the Construction Completion
     Date, except for the right to terminate this Lease in accordance with
     Section 4.2(c). Landlord hereby agrees to perform Landlord's Work and
     Landlord's Base Building Work (i) in compliance with all applicable laws,
     rules, ordinances and codes in effect as of the Commencement Date (ii) in a
     good and workmanlike manner and (iii) at Landlord's sole cost and expense
     (subject to Tenant's obligation to pay OBS Costs as hereinabove set forth).

     (b) The Premises shall be deemed "ready for occupancy" on the first
     Business Day (the "Substantial Completion Date") following written notice
     to Tenant that Landlord's Work and Landlord's Base Building Work have been
     completed except for items of work (and, if applicable, adjustment of
     equipment and fixtures) which can be completed after occupancy has been
     taken without causing substantial interference with Tenant's use of the
     Premises (i.e., so called "punch list" items) which notice shall be
     accompanied by Landlord's and the architect's certificates certified to
     Tenant that Landlord's Work and Landlord's Base Building Work have been
     substantially completed (a "Completion Certificate")  and Landlord shall
     have obtained a Final Certificate of Occupancy or an Occupancy Permit for
     the Premises (a "C of O").  It is agreed and understood that a so-called
     "conditional" or "temporary" Certificate of Occupancy or Occupancy Permit
     shall be deemed to satisfy the C of O requirement of the immediately
     preceding sentence provided that the only condition(s) to issuance of a
     Final C of O then outstanding pertain solely to matters or work which are
     the responsibility of the Tenant rather than the obligation or
     responsibility of Landlord under this Lease.  Tenant shall provide Landlord
     with the final punch list (the "Final Punch List") within Ten (10) days
     after Tenant's receipt of a Completion Certificate from Landlord's
     Architect.  Tenant shall afford Landlord access to the Premises for the
     purpose of completing the Final Punch List after the Commencement 

                                      -11-
<PAGE>
 
     Date, if necessary and such Final Punch List shall be completed within
     Thirty (30) days after Landlord's receipt of same.

     (c) If the Substantial Completion Date has not occurred by the Construction
     Completion Date (as it may be extended pursuant to Section 4.4), Tenant
     shall have the right to terminate this Lease by giving notice to Landlord,
     not later than fifteen (15) days after the Construction Completion Date (as
     so extended), of Tenant's desire so to do.  Upon the giving of such notice
     within the time and manner required, this Lease shall cease and come to an
     end without further liability or obligation on the part of either party and
     Landlord shall release any security then being held by Landlord under this
     Lease on the date which is the first to occur of (i) the date which is
     seventy five (75) days after the giving of such notice (which 75 day period
     shall be automatically extended by delays in Substantial Completion caused
     by Force Majeure) or (ii) March 1, 1996 (the "Outside Date"), unless,
     within such period, Landlord substantially completes Landlord's Work to the
     extent required by Section 4.2(b) above, which substantial completion shall
     void Tenant's election to terminate; and such right of termination shall be
     Tenant's sole and exclusive remedy at law or in equity for Landlord's
     failure so to complete such work within such time.

     4.3            CONCLUSIVENESS OF LANDLORD'S PERFORMANCE. Unless Tenant
                    -----------------------------------------              
     shall have given Landlord written notice by the end of the first full
     calendar year after the Commencement Date of specific respects in which
     Landlord has not performed Landlord's Work and Landlord's Base Building
     Work in compliance with the matters set forth in Exhibit B and the final
     approved Tenant's Plans, Tenant shall have no claim that Landlord has
     failed to perform any of Landlord's Work or Landlord's Base Building Work.
     Except for Landlord's Work and Landlord's Base Building Work and except as
     otherwise expressly provided in this Lease, the Premises are being leased
     in their condition, "as is" without warranty or representation by Landlord.
     Landlord hereby agrees to perform Landlord's Work and Landlord's Base
     Building Work in compliance with the requirements of the Americans with
     Disabilities Act of 1990 as amended.  Tenant acknowledges that it has
     inspected the Premises and common areas of the Building and, except for
     Landlord's Work and Landlord's Base Building Work shown on Exhibit C has
     found the same to be satisfactory.

     4.4            TENANT'S DELAYS. (a) If a delay shall occur in the
                    ----------------                                  
     Substantial Completion Date as the result of:

               (i) any written request by Tenant that Landlord delay in the
     commencement or completion of Landlord's Work for any reason; or

                                      -12-
<PAGE>
 
               (ii) any requested change by Tenant in Exhibit B or Proposed
     Plans (except such changes to Proposed Plans as are required and necessary
     due to the fact that  Proposed Plans are not submitted to Tenant
     substantially in accordance with Exhibit B) Tenant's Plans or Tenant's
     failure to timely approve Proposed Plans submitted to Tenant for approval
     by Landlord; or

               (iii) any other act or omission of Tenant or its officers,
     partners, agents, servants or contractors which shall cause a delay in the
     Substantial Completion Date; or

               (iv) any requested change by Tenant with respect to Exhibit B-1;
     or

               (v) any reasonably necessary displacement of any of Landlord's
     Work from its place in Landlord's construction schedule resulting from any
     of the causes for delay referred to in clauses (i), (ii), (iii) or (iv) of
     this paragraph and the fitting of such Work back into the schedule;

     then, in any such event, Tenant shall, from time to time and within ten
     (10) days after demand therefor, pay to Landlord for each day the
     Substantial Completion Date is delayed by reason of the delays referred to
     in clauses (i), (ii), (iii), (iv) or (v) above, an amount equal to one day
     of Basic Rent (pro-rated on a daily basis) for each such day of delay.
     Landlord shall provide Tenant with written notice of any circumstances
     which will result in a Tenant's Delay within a reasonable time after
     Landlord or Landlord's agents, employees or contractors shall have actual
     knowledge and notice of the occurrence of any such circumstances.  Landlord
     shall provide Tenant with written notice of any claimed Tenant's Delay.

     (b) The delays referred to in paragraph (a) are herein referred to
     collectively and individually as "Tenant's Delay".

     (c) If, as a result of Tenant's Delay, the Substantial Completion Date is
     delayed in the aggregate for more than seventy five (75) days, Landlord may
     (but shall not be required to) at any time thereafter terminate this Lease
     by giving written notice of such termination to Tenant and thereupon this
     Lease shall terminate without further liability or obligation on the part
     of either party, except that Tenant shall pay to Landlord the cost
     theretofore incurred by Landlord in performing Landlord's Work, plus an
     amount equal to Landlord's out-of-pocket expenses incurred in connection
     with this Lease, including, without limitation, brokerage and reasonable
     legal fees, together with any amount required to be paid pursuant to
     paragraph (a) through the effective termination date.

                                      -13-
<PAGE>
 
     (d) The Construction Completion Date and the Outside Date (as defined in
     Section 4.2(c) shall automatically be extended for the period of any delays
     caused by Tenant's Delay.

     4.5 LANDLORD'S BASE BUILDING WORK.  Landlord hereby agrees to perform the
         -----------------------------                                        
     work and provide the materials necessary to complete the improvements
     referenced in Exhibit C hereto ("Landlord's Base Building Work") at
     Landlord's sole cost and expense on or before the Commencement Date.

     4.6 SATELLITE DISH.  To the extent permitted by applicable laws, rules,
         --------------                                                     
     ordinances and codes of the Town of Burlington or any other state or
     federal agency having jurisdiction, Landlord will not unreasonably withhold
     or delay its consent to the installation of up to ten (10) rooftop
     satellite dishes on the roof of the building.  Such satellite dishes shall
     be used solely by Tenant in the course and conduct of its business and
     Tenant shall not grant others the right to use same.  Tenant shall be
     responsible for all costs and expenses associated with the installation,
     maintenance and repair of said rooftop satellite dishes.  The location of
     any such dish shall be subject to the mutual agreement of Landlord and
     Tenant which shall not be unreasonably withheld or delayed.  Upon
     expiration or earlier termination of the Lease, Tenant shall remove such
     satellite dishes from the roof of the building and repair any damage to the
     roof of the building caused by the installation and/or removal of such
     satellite dishes.  Tenant hereby acknowledges and agrees that Landlord
     makes no representation or warranty as to whether or not installation of
     rooftop satellite dishes is permitted in accordance with applicable laws of
     the Town of Burlington and/or any other state,  local or federal agency.
     Tenant hereby acknowledges and agrees that responsibility for compliance of
     law with respect to such satellite dishes shall be the sole and exclusive
     responsibility of the Tenant.  Notwithstanding anything to the contrary in
     this Lease, Tenant shall be solely responsible for any damages or the cost
     of any repairs to or replacements of the building roof system resulting
     from the installation, removal or maintenance of the satellite dishes by
     Tenant.

     4.7    TENANT'S ADDITIONAL WORK.  Attached as Exhibit B-1 is a description
            -------------------------                                          
     of certain work and improvements which Tenant has requested that Landlord
     perform ("Tenant's Additional Work").  Landlord and Tenant hereby approve
     all matters described in Exhibit B-1.  Landlord shall perform Tenant's
     Additional Work in compliance with all applicable laws and in a good and
     workmanlike manner.

     As an additional charge under this Lease, Tenant shall reimburse Landlord
     for all costs and expenses incurred by Landlord in connection with
     performing Tenant's Additional Work in the amounts shown on Exhibit

                                      -14-
<PAGE>
 
     B-1 as and when Tenant is invoiced therefor by Landlord, but in no event
     later than thirty (30) days after such invoice.  If Tenant shall request
     and Landlord shall agree to perform any modifications or changes to Exhibit
     B-1, Tenant shall also be responsible for any costs or expenses incurred by
     Landlord in connection with performing the work resulting from modification
     or change to B-1.  Notwithstanding the foregoing to the contrary, Landlord
     shall be responsible for the first $25,000.00 of the cost of Tenant's
     Additional Work.

                                   ARTICLE V
                                   ---------

                                USE OF PREMISES
                                ---------------


      5.1  PERMITTED USE. (a) Tenant agrees that the Premises shall be used and
           --------------                                                      
      occupied by Tenant only for Permitted Uses.

      (b) Tenant agrees to conform to the following provisions during the Term
      of this Lease:

            (i) Tenant shall cause all freight to be delivered to or removed
      from the Building and the Premises in accordance with reasonable rules and
      regulations established by Landlord therefor;

            (ii) Except as expressly permitted in Section 14.30 hereof, Tenant
      will not place on the exterior of the Premises (including both interior
      and exterior surfaces of doors and interior surfaces of windows) or on any
      part of the Building outside the Premises, any signs, symbol,
      advertisements or the like visible to public view outside of the Premises.
      Landlord will not unreasonably withhold consent for signs or lettering in
      Tenant's reception area or on the entry doors to the Premises provided
      such signs conform to building standards adopted by Landlord and Tenant
      has submitted a sketch of the sign to be placed on such entry doors.

       In addition to the foregoing, at such time as the Tenant is the sole
       tenant of the Building (and only during such times as Tenant is the sole
       Tenant of the Building) Landlord shall not unreasonably withhold or delay
       its consent to Tenant installing signage consisting of Tenant's name on
       the exterior glass main entry door to the Building.  Tenant shall remove
       any such signage upon expiration or earlier termination of the Term of
       this Lease.

            (iii) Tenant shall not perform any act or carry on any practice
       which may injure the Premises, or any other part of the Building, or
       cause offensive odors or loud 

                                      -15-
<PAGE>
 
       noise or constitute a nuisance or menace to any other tenant or tenants
       or other persons in the Building;

            (iv) Tenant shall, in its use of the Premises, comply with the
       requirements of all applicable governmental laws, rules and regulations;
       and

            (v) Tenant shall only occupy the Premises for the Permitted Uses and
       for no other purposes.

      5.2  INSTALLATION AND ALTERATIONS BY TENANT. (a) Tenant shall make no
           ---------------------------------------                         
      alterations, additions (including, for the purposes hereof, wall-to-wall
      carpeting), or improvements in or to the Premises without Landlord's prior
      written consent. Any such alterations, additions or improvements shall (i)
      be in accordance with complete plans and specifications prepared by Tenant
      and approved in advance by Landlord; (ii) be performed in a good and
      workmanlike manner and in compliance with all applicable laws including,
      without limitation, the provisions of the Americans with Disabilities Act
      of 1990 and applicable regulations; (iii) be performed and completed in
      the manner required in Section 5.2(d) hereof; (iv) be made at Tenant's
      sole expense and at such times as Landlord may from time to time
      reasonably designate; and (v) become a part of the Premises and the
      property of Landlord unless Landlord shall require removal thereof by
      Tenant upon expiration or earlier termination of the Term of this Lease or
      if Tenant shall advise Landlord that Tenant intends to remove same upon
      expiration of this Lease, by written notice to Landlord either at the time
      Tenant shall request permission to install same or no later than nine (9)
      months prior to expiration of the Term of this Lease.  Tenant shall repair
      any damage occasioned by such removal.  Notwithstanding the foregoing to
      the contrary, Landlord will not unreasonably withhold or delay its consent
      to non-structural and non-mechanical alterations or improvements to the
      Premises.

      (b) All articles of personal property and all business fixtures, machinery
      and equipment and furniture owned or installed by Tenant solely at its
      expense in the Premises ("Tenant's Removable Property") shall remain the
      property of Tenant and may be removed by Tenant at any time prior to the
      expiration of this Lease, provided that Tenant, at its expense, shall
      repair any damage to the Building caused by such removal.

      (c) Notice is hereby given that Landlord shall not be liable for any labor
      or materials furnished or to be furnished to Tenant upon credit, and that
      no mechanic's or other lien for any such labor or materials shall attach
      to or affect the reversion or other estate or interest of Landlord in and
      to the Premises. Whenever and as often as any mechanic's lien shall have
      been filed against the 

                                      -16-
<PAGE>
 
      Premises based upon any act or interest of Tenant or of anyone claiming
      through Tenant, Tenant shall forthwith take such actions by bonding,
      deposit or payment as will remove or satisfy the lien.

      (d) All of the Tenant's alterations, additions and installation of
      furnishings shall be coordinated with any work being performed by Landlord
      and in such manner as to maintain harmonious labor relations and not
      damage the Property or interfere with Building construction or operation
      and, except for installation of furnishings, shall be performed by
      contractors or workmen first approved by Landlord, which approval will not
      be unreasonably withheld or delayed.  Installation and moving of
      furnishings, equipment and the like shall be performed only with labor
      compatible with that being employed by Landlord for work in or to the
      Building and not to employ or permit the use of any labor or otherwise
      take any action which might result in a labor dispute involving personnel
      providing services in the Building.  Except for work by Landlord's general
      contractor, Tenant before its work is started shall:  secure all licenses
      and permits necessary therefor; deliver to Landlord a statement of the
      names of all its contractors and subcontractors and the estimated cost of
      all labor and material to be furnished by them; and cause each contractor
      to carry workmen's compensation insurance in statutory amounts covering
      all the contractor's and subcontractor's employees and comprehensive
      public liability insurance and property damage insurance with such limits
      as Landlord may reasonably require but in no event less than a combined
      single limit of Two Million and No/100ths ($2,000,000.00) Dollars (all
      such insurance to be written in companies approved by Landlord and
      insuring Landlord and Tenant as well as the contractors), and to deliver
      to Landlord certificates of all such insurance.  Tenant agrees to pay
      promptly when due the entire cost of any work done on the Premises by
      Tenant, its agents, employees, or independent contractors, and not to
      cause or permit any liens for labor or materials performed or furnished in
      connection therewith to attach to the Premises or the Property and to
      discharge any such liens which may so attach within thirty (30) days of
      attachment and, at the request of Landlord to deliver to Landlord
      performance bonds as to work that has an aggregate cost of completion in
      excess of $100,000.00.  Upon completion of any work done on the Premises
      by Tenant, its agents, employees, or independent contractors, Tenant shall
      promptly deliver to Landlord original lien releases and waivers executed
      by each contractor, subcontractor, supplier, materialmen, architect,
      engineer or other party which furnished labor, materials or other services
      in connection with such work and pursuant to which all liens, claims and
      other rights of such party with respect to labor, material or services
      furnished in connection with such work are unconditionally released and
      waived.

                                      -17-
<PAGE>
 
                                   ARTICLE VI
                                   ----------

                           ASSIGNMENT AND SUBLETTING
                           -------------------------


      6.1  PROHIBITION. (a) Except as otherwise expressly provided in this
           ------------                                                   
      Lease, Tenant covenants and agrees that whether voluntarily,
      involuntarily, by operation of law or otherwise, neither this Lease nor
      the term and estate hereby granted, nor any interest herein or therein,
      will be assigned, mortgaged, pledged, encumbered or otherwise transferred
      and that neither the Premises nor any part thereof will be encumbered in
      any manner by reason of any act or omission on the part of Tenant, or used
      or occupied, by anyone other than Tenant, or for any use or purpose other
      than a Permitted Use, or be sublet (which term, without limitation, shall
      include granting of concessions, licenses and the like) in whole or in
      part, or be offered or advertised for assignment or subletting.

      (b) The provisions of paragraph (a) of this Section shall not apply to
      transactions with an entity into or with which Tenant is merged or
      consolidated or to which substantially all of Tenant's assets are
      transferred or to any entity which controls or is controlled by Tenant or
      is under common control with Tenant, provided that in any of such events
      (i) the successor to Tenant has a net worth computed in accordance with
      generally accepted accounting principles at least equal to the net worth
      of Tenant immediately prior to such merger, consolidation or transfer,
      (ii) proof reasonably satisfactory to Landlord of such net worth shall
      have been delivered to Landlord at least 10 days prior to the effective
      date of any such transaction, and (iii) the assignee agrees directly with
      Landlord, by written instrument in form reasonably satisfactory to
      Landlord, to be bound by all the obligations of Tenant hereunder
      including, without limitation, the covenant against further assignment or
      subletting.

      (c) If this Lease be assigned, or if the Premises or any part thereof be
      sublet or occupied by anyone other than Tenant, Landlord may, at any time
      and from time to time, collect rent and other charges from the assignee,
      subtenant or occupant, and apply the net amount collected to the rent and
      other charges herein reserved, but no such assignment, subletting,
      occupancy, collection or modification of any provisions of this Lease
      shall be deemed a waiver of this covenant, or the acceptance of the
      assignee, subtenant or occupant as a tenant or a release of the original
      named Tenant from the further performance by the original named Tenant
      hereunder. No assignment or subletting hereunder shall relieve Tenant from
      its obligations hereunder and Tenant shall remain fully and 

                                      -18-
<PAGE>
 
      primarily liable therefor. No assignment or subletting, or occupancy shall
      affect Permitted Uses.

           (d) In connection with any request by Tenant for consent to
      assignment or subletting, Tenant shall first submit to Landlord in
      writing: (i) the name of the proposed assignee or subtenant, (ii) such
      information as to its financial responsibility and standing as Landlord
      may reasonably require, and (iii) all terms and provisions upon which the
      proposed assignment or subletting is to be made. Upon receipt from Tenant
      of such request and information, the Landlord shall have an option
      (sometimes hereinafter referred to as the "option" or "Take Back Option")
      to be exercised in writing within fifteen (15) days after its receipt from
      Tenant of such request and information, if the request is to assign the
      Lease or to sublet all of the Premises, to cancel or terminate this Lease,
      or, if the request is to sublet a portion, of the Premises only, to cancel
      and terminate this Lease with respect to such portion, in each case, as of
      the date set forth in Landlord's notice of exercise of such option, which
      shall be not less than thirty (30) nor more than sixty (60) days following
      the giving of such notice; in the event Landlord shall exercise such
      option, Tenant shall surrender possession of the entire Premises, or the
      portion which is the subject of the option, as the case may be, on the
      date set forth in such notice in accordance with the provisions of this
      Lease relating to surrender of Premises at the expiration of the Term. If
      this Lease shall be cancelled as to a portion of the Premises only, Basic
      Rent, and Escalation Charges shall thereafter be abated proportionately
      according to the ratio the number of square feet of the portion of the
      space surrendered bears to the size of the Premises.

           If Landlord shall not exercise its option pursuant to the foregoing
      provisions, Landlord will not unreasonably delay or withhold its consent
      to the assignment or subletting to the party referred to upon all the
      terms and provisions set forth in Tenant's notice to Landlord, provided
      that the terms and provisions of such assignment or subletting shall
      specifically make applicable to the assignee or sublessee all of the
      provisions of this Article VI of the Lease so that Landlord shall have
      against the assignee or sublessee all rights with respect to any further
      assignment or subletting which are set forth in Article VI of the Lease as
      amended hereby except that no such assignee or sublessee shall have any
      right to further assign or sublet the Premises. Further, in any case where
      Landlord consents to an assignment or a subletting, Landlord shall be
      entitled to receive all Subleasing Overages (as said term is hereinafter
      defined).  As used herein, the term "Subleasing Overages" shall mean, for
      each period in question, all amounts received by Tenant in excess of Basic
      Rent, and Escalation Charges and other 

                                      -19-
<PAGE>
 
      items of additional rent reserved under this Lease attributable to the
      space sublet (including, without limitation, all lump sum payments made in
      connection therewith).

           Any such assignment or subletting shall nevertheless be subject to
      all the terms and provisions of Article VI and no assignment shall be
      binding upon Landlord or any of Landlord's mortgagees, unless Tenant shall
      deliver to Landlord an instrument in recordable form which contains a
      covenant of assumption by the assignee running to Landlord and all persons
      claiming by, through or under Landlord. The failure or refusal of the
      assignee to execute such instrument of assumption shall not release or
      discharge the assignee from its liability as Tenant hereunder. In
      addition, Tenant shall furnish to Landlord a conformed copy of any
      sublease effected under terms of this Article VI.  In no event shall the
      Tenant hereunder be released from its liability under this Lease.

           (e) Provided that Tenant shall first provide Landlord with written
      notice and the information described in clauses d(i), (ii) and (iii) of
      Section 6.1(d) hereof, Landlord shall not unreasonably withhold or delay
      its consent (nor shall the Take Back Option apply) to the subletting of up
      to 10,000 rentable square feet of the Premises (in the aggregate).  In
      addition, Landlord shall only be entitled to receive 50% of the Subleasing
      Overages attributable to a subletting made by Tenant pursuant to the
      provisions of Section 6.1(e) hereof.  Except as herein specified all other
      provisions of this Article VI shall be applicable to any such subletting
      made by Tenant pursuant to this Section 6.1 (e).

           (f) As additional rent, Tenant shall reimburse Landlord promptly for
      reasonable legal and other expenses incurred by Landlord in connection
      with any assignment or subletting under this Article VI.

 
                                  ARTICLE VII
                                  -----------

             RESPONSIBILITY FOR REPAIRS AND CONDITIONS OF PREMISES;
             ------------------------------------------------------

                      SERVICES TO BE FURNISHED BY LANDLORD
                      ------------------------------------


      7.1  LANDLORD REPAIRS. (a) Except as otherwise provided in this Lease,
           -----------------                                                
      Landlord agrees to keep in good order, condition and repair the roof,
      common areas, exterior walls (including exterior glass) and structure of
      the Building (including plumbing, mechanical and electrical systems
      installed by Landlord but excluding any Liebert hvac units serving
      Tenant's computer  room and any systems installed by Tenant or installed
      specifically for Tenant's benefit 

                                      -20-
<PAGE>
 
      after the completion of Landlord's Work pursuant to Article IV), all
      insofar as they affect the Premises, except that Landlord shall in no
      event be responsible to Tenant for the condition of glass in the Premises
      or for the doors (or related glass and finish work) leading to the
      Premises, or for any condition in the Premises or the Building caused by
      any act or neglect of Tenant, its agents, employees, invitees or
      contractors. Subject to all other applicable provisions of this Lease, if
      Landlord or Landlord's agents, servants, employees or contractors shall
      negligently perform or negligently fail to perform a repair, and as a
      result of such negligent act or omission in performing such repair, damage
      to the physical condition of the Premises shall occur, then Landlord
      shall, at its sole cost and expense, repair such physical damage to the
      Premises (exclusive of Tenant's Removable Property) resulting from such
      negligent act or omission by Landlord (and the cost of repairing such
      physical damage shall not be includable in Operating Expenses). Landlord
      shall not be responsible to make any improvements or repairs to the
      Premises or Building other than as expressly in this Section 7.1 provided,
      unless expressly provided otherwise in this Lease. Except as otherwise
      expressly provided in this Section 7.1, all costs and expenses sustained
      or incurred by Landlord in performing its obligations pursuant to this
      Section 7.1 shall be included in Operating Expenses.

      (b) Landlord shall never be liable for any failure to make repairs which
      Landlord has undertaken to make under the provisions of this Section 7.1
      or elsewhere in this Lease, unless Tenant has given notice to Landlord of
      the need to make such repairs, and Landlord has failed to commence to make
      such repairs within a reasonable time after receipt of such notice, or
      fails to proceed with reasonable diligence to complete such repairs.

      (c) Any services which Landlord is required to furnish pursuant to the
      provisions of this Lease may, at Landlord's option be furnished from time
      to time, in whole or in part, by employees of Landlord or by the Manager
      of the Property or by one or more third persons.

      7.2  TENANT'S AGREEMENT. (a) Tenant will keep neat and clean and maintain
           -------------------                                                 
      in good order, condition and repair the Premises and every part thereof,
      excepting only those repairs for which Landlord is responsible under the
      terms of this Lease, reasonable wear and tear of the Premises, and damage
      by fire or other casualty and as a consequence of the exercise of the
      power of eminent domain; and shall surrender the Premises, at the end of
      the Term, in such condition. Without limitation, Tenant shall continually
      during the Term of this Lease maintain the Premises in accordance with all
      laws, codes and ordinances from time to time in effect and all directions,
      rules and 

                                      -21-
<PAGE>
 
      regulations of the proper officers of governmental agencies having
      jurisdiction, and of the Boston Board of Fire Underwriters, and shall, at
      Tenant's own expense, obtain all permits, licenses and the like required
      by applicable law.

        Notwithstanding the foregoing provisions of this Section 7.2(a), and
      provided that Tenant is acting in good faith, Tenant shall have the right
      to contest or appeal any order by a court or governmental authority
      requiring compliance with such laws, ordinances, directions, rules or
      regulations and to negotiate compliance therewith and Tenant shall not be
      required to comply with same to the extent that Tenant is in good faith
      contesting or appealing compliance by appropriate proceedings.
      Notwithstanding anything contained in this paragraph to the contrary, in
      no event shall any such non-compliance, contest or appeal by Tenant result
      in or impose upon Landlord any criminal or civil penalties or enforcement
      actions or liabilities of any kind or nature.  Further, Tenant hereby
      agrees to indemnify and hold Landlord harmless from and against any loss,
      cost, damage, claim, injury or harm sustained or incurred by Landlord
      (including, without limitation, all costs and legal fees) as the result of
      or related to any attempted exercise or exercise of Tenant's rights to
      contest not comply or appeal as set forth in this paragraph.
      Notwithstanding the foregoing or the provisions of Article XII, Tenant
      shall be responsible for the cost of repairs which may be necessary by
      reason of damage to the Building caused by any act or neglect of Tenant or
      its agents, employees, contractors or invitees (including any damage by
      fire or any other casualty arising therefrom).

      (b) If repairs are required to be made by Tenant pursuant to the terms
      hereof, Landlord may demand that Tenant make the same forthwith, and if
      Tenant refuses or neglects to commence such repairs and complete the same
      with reasonable dispatch after such demand, Landlord may (but shall not be
      required to do so) make or cause such repairs to be made (the provisions
      of Section 14.18 being applicable to the costs thereof) and shall not be
      responsible to Tenant for any loss or damage that may accrue to Tenant's
      stock or business by reason thereof. Notwithstanding the foregoing,
      Landlord may elect to take action hereunder immediately and without notice
      to Tenant if Landlord reasonably believes an emergency to exist.

      (c) Without limitation of the foregoing provisions of this Section 7.2,
      Tenant shall throughout the Term of this Lease perform, at Tenant's sole
      cost and expense, the cleaning and janitorial services to the Premises and
      (as specified in Exhibit D) the Common Areas of the Building in accordance
      with and as and when specified in Exhibit D.  It is agreed and understood
      that Landlord shall have no 

                                      -22-
<PAGE>
 
      responsibility to clean the Premises or the Common Areas or any of the
      windows of the Building.

      7.3    FLOOR LOAD - HEAVY MACHINERY. (a) Tenant shall not place a load
             -----------------------------                                  
      upon any floor in the Premises exceeding 80 pounds per square foot and
      which is allowed by law. Landlord reserves the right to prescribe the
      weight and position of all business machines and mechanical equipment,
      including safes, which shall be placed so as to distribute the weight.
      Business machines and mechanical equipment shall be placed and maintained
      by Tenant at Tenant's expense in settings sufficient, in Landlord's
      judgment, to absorb and prevent vibration, noise and annoyance. Tenant
      shall not move any safe, heavy machinery, heavy equipment, freight, bulky
      matter or fixtures into or out of the Building without Landlord's prior
      consent, which consent shall not be unreasonably withheld or delayed but
      which may include a requirement to provide insurance, naming Landlord as
      an insured, in such amounts as Landlord may deem reasonable.

      (b) If such safe, machinery, equipment, freight, bulky matter or fixtures
      requires special handling, Tenant agrees to employ only persons holding a
      Master Rigger's License to do such work, and that all work in connection
      therewith shall comply with applicable laws and regulations. Any such
      moving shall be at the sole risk and hazard of Tenant, and Tenant will
      exonerate, indemnity and save Landlord harmless against and from any
      liability, loss, injury, claim or suit resulting directly or indirectly
      from such moving.

      7.4  BUILDING SERVICES. (a) Landlord shall furnish heating and cooling as
           ------------------                                                  
      normal seasonal changes may require to provide reasonably comfortable
      space temperature and ventilation for occupants of the Premises under
      normal business operation at an occupancy of not more than one person per
      125 square feet of Premises Rentable Area. The cost and expense of
      utilities required to provide heating, ventillation and cooling to the
      Premises shall be borne by Tenant in accordance with the provisions of
      Section 7.5 hereof. In the event Tenant introduces to the Premises
      personnel or equipment which overloads the capacity of the Building system
      or in any other way interferes with the system's ability to perform
      adequately its proper functions, supplementary systems may, if and as
      needed, at Landlord's option, be provided by Landlord, at Tenant's
      expense.

      (b) Landlord shall also provide:

            (i) Passenger elevator service from the existing passenger elevator
       system in common with Landlord and other tenants in the Building on a 24
       hour, seven (7) day a week basis.

                                      -23-
<PAGE>
 
            (ii) Cold water (at temperatures supplied by the Town of Burlington)
       for drinking, lavatory and toilet purposes on a 24 hour, seven (7) day a
       week basis. If Tenant uses water for any purpose other than for ordinary
       lavatory, shower and drinking purposes, Landlord may assess a reasonable
       charge for the additional water so used, or install a water meter and
       thereby measure Tenant's water consumption for all purposes. In the
       latter event, Tenant shall pay the cost of the meter and the cost of
       installation thereof and shall keep such meter and installation equipment
       in good working order and repair. Tenant agrees to pay for water
       consumed, as shown on such meter, together with the sewer charge based on
       such meter charges, as and when bills are rendered, and in default in
       making such payment Landlord may pay such charges and collect the same
       from Tenant as an additional charge.

            (iii) Intentionally Omitted.

            (iv) Access to the Premises seven days per week, twenty-four hours
       per day, subject to reasonable security restrictions and restrictions
       based on emergency conditions and all other applicable provisions of this
       Lease including, without limitation, the provisions of Section 7.4(a)
       hereof.

            (v) Landscaping for the exterior areas of the Property and snow and
       ice removal with respect to the parking areas, roadways and sidewalks
       located on the Property.

      (c) Landlord reserves the right to curtail, suspend, interrupt and/or stop
      the supply of water, sewage, electrical current, cleaning, and other
      services, and to curtail, suspend, interrupt and/or stop use of entrances
      and/or lobbies serving access to the Building, without thereby incurring
      any liability to Tenant, when necessary by reason of accident or
      emergency, or for repairs, alterations or replacements, in the reasonable
      judgment of Landlord desirable or necessary, or when prevented from
      supplying such services or use by strikes, lockouts, difficulty in
      obtaining materials, accidents or any other cause beyond Landlord's
      control, or by laws, orders or inability, by exercise of reasonable
      diligence, to obtain electricity, water, gas, steam, coal, oil or other
      suitable fuel or power.  No diminution or abatement of rent or other
      compensation, nor any direct, indirect or consequential damages shall or
      will be claimed by Tenant as a result of, nor shall this Lease or any of
      the obligations of Tenant be affected or reduced by reason of, any such
      interruption, curtailment, suspension or stoppage in the furnishing of the
      foregoing services or use, irrespective of the cause thereof.  Failure or
      omission on the part of Landlord to furnish any of the foregoing 

                                      -24-
<PAGE>
 
      services or use shall not be construed as an eviction of Tenant, actual or
      constructive, nor entitle Tenant to an abatement of rent, nor to render
      the Landlord liable in damages, nor release Tenant from prompt fulfillment
      of any of its covenants under this Lease. To the extent within its
      reasonable control, Landlord shall use good faith, commercially reasonable
      efforts to promptly restore any such service which is suspended,
      curtailed, stopped or interrupted.

7.5    UTILITIES.  (a) Electric service and consumption for the entire Property
       ---------                                                               
       (inclusive of the Premises, interior and exterior common areas, parking
       lots and all other vacant and occupied space in the Building) is
       presently metered by one main electric meter (the "House Meter").  The
       House Meter also measures electrical useage and consumption necessary to
       provide heating, ventillation and air conditioning to the entire Building
       Rentable Area(occupied and unoccupied) and all common areas of the
       Building.  Due to logistical and economic reasons, Landlord and Tenant
       have agreed to have the costs of electric service and consumption for the
       entire Property continue to be measured by and passed through the House
       Meter and the costs of such electrical service and consumption shall be
       allocated and paid in the manner hereafter specified.

       Until such time as Tenant is in occupancy of the entire Building Rentable
       Area, the House Meter shall be in Landlord's name and Tenant shall (as an
       additional charge under the Lease) reimburse Landlord monthly, within
       thirty days after receipt of an invoice from Landlord, for "Tenant's
       Proportionate Share" of the "Electric Charge" (as each of said terms is
       hereafter defined) based on the actual costs and expenses billed to
       Landlord as measured by the House Meter.  As used herein, the term
       "Tenant's Proportionate Share" shall mean the percentage obtained by
       dividing the Premises Rentable Area (as that amount may be adjusted
       hereunder from time to time) by the number of rentable square feet of the
       Building leased to tenants or occupants, including Tenant during such
       period.  As used herein, the term "Electric Charge" shall mean a monthly
       amount equal to the monthly amount invoiced by the applicable utility for
       all electrical use and consumption on the Property as measured and billed
       to the House Meter less the "Landlord's Electrical Share".

       As used herein, the term "Landlord's Electrical Share" shall mean a
       monthly dollar amount equal to the product obtained by multiplying (i)
       0.075 by (ii) the Vacant Square Footage Amount (as said term is hereafter
       defined).  As used herein, the term "Vacant

                                      -25-
<PAGE>
 
       Square Footage Amount" shall mean the total number of rentable square
       feet in the Building not leased during such period. (For example, if
       during the applicable calendar month for which the Electrical Charge is
       being computed, the Premises Rentable Area consisted of 30,183 rentable
       square feet and no other portion of the Building was leased, the
       Landlord's Electrical Share would be calculated as follows: .075 x
       (39,482 -30,183) = 697.42 and, accordingly, the Electric Charge for such
       month would be the total amount of the electric bill for such month less
       697.42.)

       At such time as the Premises Rentable Area consists of the entire
       Building Rentable Area, the House Meter shall be placed in Tenant's name
       and Tenant shall be responsible for all costs and expenses for
       electricity used and consumed on the Property as measured by such House
       Meter (Tenant shall then arrange to have all bills for electricity used
       and consumed at the Property as measured by the House Meter billed
       directly to and paid solely by Tenant) and there shall be no Tenant's
       Proportionate Share of the Electric Charge, no Landlord's Electrical
       Share nor any adjustment therefore.

       Landlord shall have the same rights and remedies against Tenant for
       failure to pay the Tenant's Proportionate Share of the Electric Charge as
       and when due hereunder as Landlord has against Tenant for failure to pay
       Basic Rent when due.

       (b) Natural Gas service and consumption for the entire Property
       (inclusive of the Premises, interior and exterior common areas and all
       other vacant and occupied space in the Building) is presently metered by
       one main gas meter (the "Gas Meter").  The Gas Meter also measures gas
       useage and consumption necessary to provide heating and hot water to the
       entire Building Rentable Area(occupied and unoccupied) and all common
       areas of the Building.  Due to logistical and economic reasons, Landlord
       and Tenant have agreed to have the costs of natural gas service and
       consumption for the entire Property continue to be measured by and passed
       through the Gas Meter and the costs of such gas service and consumption
       shall be allocated and paid in the manner hereafter specified.

       Until such time as Tenant is in occupancy of the entire Building Rentable
       Area, the Gas Meter shall be in Landlord's name and Tenant shall (as an
       additional charge under the Lease) reimburse Landlord monthly, within
       thirty (30) days after receipt of an invoice from Landlord, for "Tenant's
       Proportionate Share" of 

                                      -26-
<PAGE>
 
       "Gas Charges" (as each of said terms is hereafter defined) based on the
       actual costs and expenses billed to Landlord as measured by the Gas
       Meter. As used herein, the term "Tenant's Proportionate Share" shall mean
       the percentage obtained by dividing the Premises Rentable Area (as that
       amount may be adjusted hereunder from time to time) by the number of
       rentable square feet of the Building leased to tenants or occupants,
       including Tenant, during such period. As used herein, the term "Gas
       Charges" shall mean a monthly amount equal to the monthly amount invoiced
       by the applicable utility for all natural gas use and consumption on the
       Property as measured and billed to the Gas Meter less the "Landlord's Gas
       Share". As used herein, the term "Landlord's Gas Share" shall mean a
       monthly dollar amount equal to the product obtained by multiplying (i)
       0.0383 by (ii) the Vacant Square Footage Amount (as said term is defined
       in Section 7.5(a)). For example, if during the applicable calendar month
       for which the Gas Charges are being computed, the Premises Rentable Area
       consisted of 30,183 rentable square feet and no other portion of the
       Building was leased, the Landlord's Gas Share would be calculated as
       follows: 0.0383 x (39,482 -30,183) = 356.15 and, accordingly, the Gas
       Charges for such month would be the total amount of the gas bill for such
       month less 356.15.

       At such time as the Premises Rentable Area consists of the entire
       Building Rentable Area, the Gas Meter shall be placed in Tenant's name
       and Tenant shall be responsible for all costs and expenses for gas used
       and consumed on the Property as measured by such Gas Meter (Tenant shall
       then arrange to have all bills for gas used and consumed at the Property
       as measured by the Gas Meter billed directly to and paid solely by
       Tenant) and there shall be no Tenant's Proportionate Share of the Gas
       Charge, no Landlord's Gas Share nor any adjustment therefore.

       Landlord shall have the same rights and remedies against Tenant for
       failure to pay the Tenant's Proportionate Share of the Gas Charge as and
       when due hereunder as Landlord has against Tenant for failure to pay
       Basic Rent when due.

      7.6  INTERRUPTION OF ESSENTIAL SERVICES.  Notwithstanding anything
           ----------------------------------                           
      contained in this Lease (including Exhibit E) to the contrary, if (a) an
      interruption or curtailment, suspension or stoppage of an Essential
      Service (as said term is hereinafter defined) shall occur (any such
      interruption of an Essential Service being hereinafter referred to as a
      "Service Interruption"), and (b) such Service Interruption occurs or
      continues as a result of the negligence or a wrongful conduct of the
      Landlord or 

                                      -27-
<PAGE>
 
      Landlord's agents, servants, employees or contractors, and (c) such
      Service Interruption continues for more than Seven (7) Business Days after
      Landlord shall have received notice thereof from Tenant and (d) as a
      result of such Service Interruption, the conduct of Tenant's normal
      operations in the Premises are materially and adversely affected, then
      there shall be an abatement of one day's Basic Rent and Escalation Charges
      for each day during which such Service Interruption continues (beginning
      with or relating back to the first day of such Service Interruption);
      provided, further, however, that if any part of the Premises is reasonably
      useable for Tenant's normal business operations or if Tenant conducts all
      or any part of its operations in and portion of the Premises
      notwithstanding such Service Interruption, then the amount of each daily
      abatement of Basic Rent and Escalation Charges shall only be proportionate
      to the nature and extent of the interruption of Tenant's normal
      operations. The rights granted under this paragraph shall be personal to
      the original Tenant and shall terminate upon any assignment of the Lease
      or any subletting of all or any portion of the Premises outstanding at any
      one time. For purposes hereof, the term "Essential Services" shall mean
      the following services: access to the Premises, heating, air-conditioning,
      water, sewer service and electricity, but only to the extent that Landlord
      has an obligation to provide same to Tenant under this Lease. Any
      abatement of Basic Rent and Escalation Charges under this paragraph shall
      apply only with respect to Basic Rent allocable to the period after each
      of the conditions set forth in subsections (a) through (d) hereof shall
      have been satisfied and only during such times as each of such conditions
      shall exist.

7.7    DEFAULT BY LANDLORD REGARDING HVAC SERVICES.
       --------------------------------------------

        (a) If (i) Landlord shall fail to perform any of Landlord's repair
      obligations under Section 7.1 of this Lease with respect to the Heating,
      Ventilating and Cooling ("HVAC") System servicing the Premises, (ii)
      Tenant's use and enjoyment of the Premises are materially and adversely
      affected as a result of such failure, and (iii) if Landlord shall fail to
      perform, cure or commence to perform such repair obligation within 48
      hours after Landlord's receipt of written notice from Tenant (by fax or
      in-hand delivery) of the repair in question and, in reasonable detail, the
      proposed remedial action and the estimated cost of performance thereof
      then, subject to the terms and provisions hereafter set forth, Tenant
      shall have the right to perform such repairs.  Tenant shall invoice
      Landlord for the fair, reasonable and competitive cost of such remedial
      action, which costs shall be payable by Landlord to Tenant within thirty
      (30) days after invoice.  (Tenant shall provide Landlord with reasonable
      documentation and evidence of the amounts so expended by 

                                      -28-
<PAGE>
 
      Tenant in the form of copies of actual vendor invoices for such work). In
      no event shall Tenant be entitled to perform any such repairs in the event
      that Landlord has commenced to cure and is diligently prosecuting the same
      to completion prior to Tenant commencing to cure the same.

        (b) Tenant will in no event be entitled to any such exercise of self-
      help rights if the cause of any failure of Landlord to act is the result
      of any act or omission of Tenant or any employee, agent, invitee or
      contractor of Tenant.

        (c) The rights granted to Tenant in this Section 7.7 shall be Tenant's
      sole exclusive right and remedy against Landlord both at law and in equity
      for Landlord's failure to perform Landlord's repair obligations as to the
      HVAC System serving the Premises under this Article VII.

        (d) The costs and expenses incurred by Landlord in connection with
      reimbursing Tenant pursuant to this Section 7.7 shall be deemed Operating
      Expenses pursuant to Exhibit E hereof but only to the extent includable in
      Operating Expenses pursuant to Exhibit E had Landlord (rather than Tenant)
      performed such work.

                                  ARTICLE VIII
                                  ------------

                               REAL ESTATE TAXES
                               -----------------


      8.1  PAYMENTS ON ACCOUNT OF REAL ESTATE TAXES. (a) For the purposes of
           -----------------------------------------                        
      this Article, the term "Tax Year" shall mean the twelve-month period
      commencing on the July 1 immediately preceding the Commencement Date and
      each twelve-month period thereafter commencing during the Term of this
      Lease; and the term "Taxes" shall mean real estate taxes assessed with
      respect to the Property for any Tax Year together with any and all
      betterment assessments, whether general or special assessed against the
      Property (regardless of when assessed).  Taxes shall not include
      inheritance taxes, estate taxes, transfer taxes, net income taxes nor
      capital stock taxes of Landlord.

      (b) In the event that, for any reason, Taxes shall be greater during any
      Tax Year than Base Taxes, Tenant shall pay to Landlord, as an Escalation
      Charge, an amount equal to (i) the excess of Taxes over Base Taxes,
      multiplied by (ii) the Escalation Factor, such amount to be apportioned
      for any fraction of a Tax Year in which the Commencement Date falls or the
      Term of this Lease ends.  Tenant's payment obligations under this Article
      VIII shall begin with the Fiscal Tax Year beginning on July 1, 1996.

      (c) Estimated payments by Tenant on account of Taxes shall be made monthly
      and at the time and in the fashion herein 

                                      -29-
<PAGE>
 
      provided for the payment of Basic Rent. The monthly amount so to be paid
      to Landlord shall be sufficient to provide Landlord by the time real
      estate tax payments are due a sum equal to Tenant's required payments, as
      estimated by Landlord from time to time, on account of Taxes for the then
      current Tax Year. Promptly after receipt by Landlord of bills for such
      Taxes, Landlord shall advise Tenant of the amount thereof and the
      computation of Tenant's payment on account thereof (accompanied by a copy
      of the applicable tax bills). If estimated payments theretofore made by
      Tenant for the Tax Year covered by such bills exceed the required payments
      on account thereof for such Year, Landlord shall credit the amount of
      overpayment against subsequent obligations of Tenant on account of Taxes
      (or refund such overpayment if the Term of this Lease has ended and Tenant
      has no further obligation to Landlord); but if the required payments on
      account thereof for such Year are greater than estimated payments
      theretofore made on account thereof for such Year, Tenant shall make
      payment to Landlord within 30 days after being so advised by Landlord.
      Landlord shall have the same rights and remedies for the non-payment by
      Tenant of any payments due on account of Taxes as Landlord has hereunder
      for the failure of Tenant to pay Basic Rent.

      8.2  ABATEMENT. If Landlord shall receive any tax refund or reimbursement
           ----------                                                          
      of Taxes or sum in lieu thereof with respect to any Tax Year which is not
      due to vacancies in the Building, then out of any balance remaining
      thereof after deducting Landlord's expenses reasonably incurred in
      obtaining such refund, Landlord shall pay to Tenant, provided there does
      not then exist a Default of Tenant, an amount equal to such refund or
      reimbursement or sum in lieu thereof (exclusive of any interest)
      multiplied by the Escalation Factor; provided, that in no event shall
      Tenant be entitled to receive more than the payments made by Tenant on
      account of real estate tax increases for such Year pursuant to paragraph
      (b) of Section 8.1 or to receive any payments or abatement of Basic Rent
      if Taxes for any Year are less than Base Taxes or Base Taxes are abated.

      8.3  ALTERNATE TAXES. (a) If some method or type of taxation shall replace
           ----------------                                                     
      the current method of assessment of real estate taxes in whole or in part,
      or the type thereof, or if additional types of taxes are imposed upon the
      Property or Landlord relating to the Property, Tenant agrees that Tenant
      shall pay a proportionate share of the same as an additional charge
      computed in a fashion consistent with the method of computation herein
      provided, to the end that Tenant's share thereof shall be, to the maximum
      extent practicable, comparable to that which Tenant would bear under the
      foregoing provisions.

                                      -30-
<PAGE>
 
      (b) If a tax (other than Federal or State net income tax) is assessed on
      account of the rents or other charges payable by Tenant to Landlord under
      this Lease, Tenant agrees to pay the same as an additional charge within
      ten (10) days after billing therefor, unless applicable law prohibits the
      payment of such tax by Tenant.


                                   ARTICLE IX
                                   ----------

                               OPERATING EXPENSES
                               ------------------


      9.1  DEFINITIONS. For the purposes of this Article, the following terms
           ------------                                                      
      shall have the following respective meanings:

            (i) Operating Year: Each calendar year in which any part of the Term
      of this Lease shall fall.

            (ii) Operating Expenses: The aggregate costs or expenses reasonably
      incurred by Landlord with respect to the operation, administration,
      repair, maintenance and management of the Property (but specifically
      excluding Utility Expenses) all as set forth in Exhibit E annexed hereto,
      provided that, if during any portion of the Operating Year for which
      Operating Expenses are being computed, less than all of Building Rentable
      Area was occupied by tenants or if Landlord is not supplying all tenants
      with the services being supplied hereunder, actual Operating Expenses
      incurred shall be reasonably extrapolated by Landlord on an item by item
      basis to the estimated Operating Expenses that would have been incurred if
      the Building were fully occupied for such entire Operating Year and such
      services were being supplied to all tenants, and such extrapolated amount
      shall, for the purposes hereof, be deemed to be the Operating Expenses for
      such Year.

            (iii) Utility Expenses: The aggregate costs or expenses incurred by
       Landlord with respect to supplying water and sewer  to the Property and
       not paid for directly by tenants, provided that, if during any portion of
       the Operating Year for which Utility Expenses are being computed, less
       than all of the Building Rentable Area was occupied by tenants or if
       Landlord is not supplying all tenants with the utilities being supplied
       hereunder, actual Utility Expenses incurred shall be reasonably
       extrapolated by Landlord on an item-by-item basis to the estimated
       Utility Expenses that would have been incurred if the Building were fully
       occupied for such Year and such utilities were being supplied to all
       tenants, and such extrapolated amount shall, for the purposes hereof, be
       deemed to be the Utility Expenses for such Operating Year.  It is agreed
       and understood that 

                                      -31-
<PAGE>
 
       only water and sewer charges and not the costs of electricity and natural
       gas described in Section 7.5(a) and (b) hereof shall be included in
       Utility Expenses.

      9.2  TENANT'S PAYMENTS. (a) In the event that for any Operating Year
           ------------------                                             
      Operating Expenses shall exceed Base Operating Expenses, Tenant shall pay
      to Landlord, as an Escalation Charge, an amount equal to (i) such excess
      Operating Expenses multiplied by (ii) the Escalation Factor, such amount
      to be apportioned for any partial Operating Year in which the Term of this
      Lease ends.

      (b) Tenant shall pay to Landlord, as an Escalation Charge, an amount equal
      to (i) Utility Expenses (as defined in 9.1(iii)) multiplied by (ii) the
      Escalation Factor, such amount to be apportioned for any partial Operating
      Year in which the Commencement Date falls or the Term of this Lease ends.

      (c) Estimated payments by Tenant on account of Operating Expenses and
      Utility Expenses shall be made monthly and at the time and in the fashion
      herein provided for the payment of Basic Rent. The monthly amount so to be
      paid to Landlord shall be sufficient to provide Landlord by the end of
      each Operating Year a sum equal to Tenant's required payments, as
      estimated by Landlord from time to time during each Operating Year, on
      account of Operating Expenses and Utility Expenses for such Operating
      Year. After the end of each Operating Year, Landlord shall submit to
      Tenant a reasonably detailed accounting of Operating Expenses and Utility
      Expenses for such Operating Year, and Landlord shall certify to the
      accuracy thereof. If estimated payments theretofore made for such
      Operating Year by Tenant exceed Tenant's required payment on account
      thereof for such Operating Year, according to such statement, Landlord
      shall credit the amount of overpayment against subsequent obligations of
      Tenant with respect to Operating Expenses and Utility Expenses (or refund
      such overpayment if the Term of this Lease has ended and Tenant has no
      further obligation to Landlord), but, if the required payments on account
      thereof for such Operating Year are greater than the estimated payments
      (if any) theretofore made on account thereof for such Operating Year,
      Tenant shall make payment to Landlord within thirty (30) days after being
      so advised by Landlord. Landlord shall have the same rights and remedies
      for the nonpayment by Tenant of any payments due on account of Operating
      Expenses and Utility Expenses as Landlord has hereunder for the failure of
      Tenant to pay Basic Rent.


                                   ARTICLE X
                                   ---------

                    INDEMNITY AND PUBLIC LIABILITY INSURANCE
                    ----------------------------------------

                                      -32-
<PAGE>
 
      10.1    TENANT'S INDEMNITY. To the maximum extent this agreement may be
              -------------------                                            
      made effective according to law, Tenant agrees to defend, indemnify and
      save harmless Landlord from and against all claims, loss, liability, costs
      and damages of whatever nature arising from any default by Tenant under
      this Lease and the following: (i) from any accident, injury, death or
      damage whatsoever to any person, or to the property of any person,
      occurring in or about the Premises; (ii) from any accident, injury, death
      or damage occurring outside of the Premises but on the Property, where
      such accident, damage or injury results or is claimed to have resulted
      from an act or omission on the part of Tenant or Tenant's agents,
      employees, invitees or independent contractors; or (iii) in connection
      with the conduct or management of the Premises or of any business therein,
      or any thing or work whatsoever done, or any condition created in or about
      the Premises; and, in any case, occurring after the date of this Lease,
      until the end of the Term of this Lease, and thereafter so long as Tenant
      is in occupancy of the Premises. This indemnity and hold harmless
      agreement shall include indemnity against all costs, expenses and
      liabilities incurred in, or in connection with, any such claim or
      proceeding brought thereon, and the defense thereof, including, without
      limitation, reasonable attorneys' fees and costs at both the trial and
      appellate levels.  The provisions of this Section 10.1 shall survive the
      expiration or any earlier termination of this Lease.  Nothing contained in
      this Section 10.1 shall require Tenant to indemnify Landlord from the
      negligence of Landlord or the negligence of Landlord's agents, servants,
      employees or contractors.

      10.2  PUBLIC LIABILITY INSURANCE. Tenant agrees to maintain in full force
            ---------------------------                                        
      from the date upon which Tenant first enters the Premises for any reason,
      throughout the Term of this Lease, and thereafter so long as Tenant is in
      occupancy of any part of the Premises, a policy of general liability and
      property damage insurance (including broad form contractual liability,
      independent contractor's hazard and completed operations coverage) under
      which Landlord, Manager (and such other persons as are in privity of
      estate with Landlord as may be set out in notice from time to time) and
      Tenant are named as insureds, and under which the insurer agrees to
      defend, indemnify and hold Landlord, Manager, and those in privity of
      estate with Landlord, harmless from and against all cost, expense and/or
      liability arising out of or based upon any and all claims, accidents,
      injuries and damages set forth in Section 10.1. Each such policy shall be
      non-cancellable and non-amendable with respect to Landlord, Manager and
      Landlord's said designees without thirty (30) days' prior notice to
      Landlord and shall be in at least the amounts of the Initial Public
      Liability Insurance specified in Section 1.3 or such greater amounts as a
      mortgagee of the Property 

                                      -33-
<PAGE>
 
      shall from time to time reasonably request in connection with the placing
      of new financing on the Property (but in no event shall such mortgagee
      have the right to require more than 150% of the then existing coverages
      hereunder) and a certificate thereof shall be delivered to Landlord.

       10.3  TENANT'S RISK. To the maximum extent this agreement may be made
             --------------                                                 
       effective according to law, Tenant agrees to use and occupy the Premises
       and to use such other portions of the Property as Tenant is herein given
       the right to use at Tenant's own risk; and except for Landlord's
       obligation to repair physical damage to the physical condition of the
       Premises caused by Landlord's negligent acts or omissions in performing
       Landlord's repair obligations as provided in Section 7.1, Landlord shall
       have no responsibility or liability for any loss of or damage to Tenant's
       Removable Property or for any inconvenience, annoyance, interruption or
       injury to business arising from Landlord's making any repairs or changes
       which Landlord is permitted by this Lease or required by law to make in
       or to any portion of the Premises or other sections of the Property, or
       in or to the fixtures, equipment or appurtenances thereof. Tenant shall
       carry "all-risk" property insurance on a "replacement cost" basis
       (including so-called improvements and betterments), and provide a waiver
       of subrogation as required in Section 14.20. The provisions of this
       Section 10.3 shall be applicable from and after the execution of this
       Lease and until the end of the Term of this Lease, and during such
       further period as Tenant may use or be in occupancy of any part of the
       Premises or of the Building.

      10.4  INJURY CAUSED BY THIRD PARTIES. To the maximum extent this agreement
            -------------------------------                                     
      may be made effective according to law, Tenant agrees that Landlord shall
      not be responsible or liable to Tenant, or to those claiming by, through
      or under Tenant, for any loss or damage that may be occasioned by or
      through the acts or omissions of persons occupying adjoining premises or
      any part of the premises adjacent to or connecting with the Premises or
      any part of the Property or otherwise.  The provisions of this Section
      10.4 shall survive the expiration or any earlier termination of this
      Lease.

       10.5  LANDLORD'S INSURANCE.  Landlord shall maintain and keep in effect
             --------------------                                             
       throughout the term of this Lease (a) insurance against loss or damage to
       the Building by fire or other casualty as may be included within either
       fire and extended coverage insurance or "all-risk" insurance in an amount
       equal to the full replacement cost of the Building (exclusive of
       foundations) and (b) comprehensive general liability insurance in amounts
       reasonably determined by Landlord.  Such coverage may be effected
       directly and/or through the use of blanket insurance coverage covering
       more than one location and may contain such reasonable deductibles as
       Landlord may elect.

                                      -34-
<PAGE>
 
                                   ARTICLE XI
                                   ----------

                         LANDLORD'S ACCESS TO PREMISES
                         -----------------------------


      11.1  LANDLORD'S RIGHTS. Landlord shall have the right, upon reasonable
            ------------------                                               
      advance written or oral notice to Tenant (except in the case of emergency
      when no notice shall be necessary), to enter the Premises at all
      reasonable hours for the purpose of inspecting or making repairs to the
      same, and Landlord shall also have the right to make access available at
      all reasonable hours and upon advance oral or written notice to Tenant to
      prospective or existing mortgagees, purchasers or tenants of any part of
      the Property and, during the last nine (9) months of the Term of the Lease
      to enter the Premises in order to show the Premises to prospective
      tenants.  In exercising its rights pursuant to this Section 11.1, Landlord
      shall use good faith, commercially reasonable efforts to avoid unnecessary
      interference with Tenant's use of the Premises.


                                  ARTICLE XII
                                  -----------

                           FIRE, EMINENT DOMAIN, ETC.
                           --------------------------


      12.1    ABATEMENT OF RENT. If the Premises shall be damaged by fire or
              ------------------                                            
      casualty, Basic Rent, Escalation Charges, Tenant's Proportionate Share of
      the Electric Charges and Tenant's Proportionate Share of Gas Charges
      payable by Tenant shall abate proportionately for the period in which, by
      reason of such damage, there is substantial interference with Tenant's use
      of the Premises, having regard to the extent to which Tenant may be
      required to discontinue Tenant's use of all or a portion of the Premises,
      but such abatement or reduction shall end if and when Landlord shall have
      substantially restored the Premises (excluding any alterations, additions
      or improvements made by Tenant pursuant to Section 5.2) to the condition
      in which they were prior to such damage. If the Premises shall be affected
      by any exercise of the power of eminent domain, Basic Rent, Escalation
      Charges, Tenant's Proportionate Share of the Electric Charges and Tenant's
      Proportionate Share of Gas Charges payable by Tenant shall be justly and
      equitably abated and reduced according to the nature and extent of the
      loss of use of the Premises suffered by Tenant. In no event shall Landlord
      have any liability for damages to Tenant for inconvenience, annoyance, or
      interruption of business arising from such fire, casualty or eminent
      domain.

                                      -35-
<PAGE>
 
      12.2  RIGHT OF TERMINATION.  If the Premises or the Building are damaged
            ---------------------                                             
      by fire or casualty, Landlord shall cause an independent contractor
      selected by it to make a written estimate (the "Estimate") of the amount
      of time normally required in the ordinary course to perform and
      substantially complete the restoration of the damage in question, and a
      copy of the Estimate shall be furnished to both Landlord and Tenant within
      sixty (60) days after the applicable casualty.  If (a) the Premises or the
      Building are substantially damaged by fire or casualty (the term
      "substantially damaged" meaning damage of such a character that the same
      cannot, as set forth in the Estimate, reasonably be expected to be
      repaired within sixty (60) days from the time the repair work would
      commence), or (b) any Mortgagee then holding a Mortgage on the Property or
      any interest of Landlord therein, should require that insurance proceeds
      payable as a result of a fire, casualty or action by taking authority be
      applied to the Mortgage debt or (c) if any part of the Building is taken
      by any exercise of the right of eminent domain, then, in the case of (a),
      (b), or (c) above, Landlord shall have the right to terminate this Lease
      (even if Landlord's entire interest in the Premises may have been
      divested) by giving notice of Landlord's election so to do within (i)
      thirty (30) days after Landlord's receipt of the Estimate in the case of a
      fire or casualty or (ii) 60 days after the effective date of the action
      described in (b) or (c) above, whereupon this Lease shall terminate thirty
      (30) days after the date of such notice with the same force and effect as
      if such date were the date originally established as the expiration date
      hereof.

      12.3  RESTORATION; TENANT'S RIGHT OF TERMINATION. (a) If this Lease shall
            -------------------------------------------                        
      not be terminated pursuant to Section 12.2 and if the amount of time
      normally required to perform and substantially complete such restoration
      in the ordinary course as set forth in the Estimate exceeds One Hundred
      Eighty (180) days from the date of the casualty, then Tenant shall have
      the right to terminate this Lease effective as of the date of Tenant's
      Termination Notice, such right to be exercised, if at all, by written
      notice (a "Tenant's Termination Notice") to Landlord within twenty (20)
      days after receipt of the Estimate.  Failure of Tenant to exercise such
      right within the time and manner herein provided shall constitute a waiver
      of such right by Tenant, time being of the essence.  Any termination of
      this Lease by Tenant pursuant to this Section 12.3(a) shall have the same
      force and effect as if such date were the date originally established as
      the date of expiration of the Lease.

        (b) If the Premises is damaged by fire or casualty or as a result of a
      taking and if this Lease shall not be terminated pursuant to Section 12.2
      or 12.3(a), Landlord shall thereafter use due diligence to restore the
      Premises 

                                      -36-
<PAGE>
 
      to substantially its condition prior to such fire or casualty, as
      described in Section 12.1. Landlord's obligation to restore shall be
      limited to the amount of insurance proceeds actually made available to the
      Landlord for the purpose of restoration or the condemnation awards
      actually made available to Landlord therefor and provided, further, that
      Landlord shall have no obligation to restore the Premises or the Building
      as and to the extent the same cannot be lawfully restored under then
      applicable zoning and building laws. If, for any reason, restoration of
      the Premises to the condition required hereby shall not be substantially
      completed as aforesaid within the One Hundred Eighty (180) day period set
      forth in 12.3(a) hereof (which One Hundred Eighty (180) day period shall
      be extended due to Force Majeure or any reason beyond the control of
      Landlord, but in no event for more than an additional Twenty (20) days),
      Tenant shall have the right to terminate this Lease by giving notice to
      Landlord thereof within Thirty (30) days after the expiration of such
      period (as so extended). Upon the giving of such notice, this Lease shall,
      effective as of the date of giving such notice, cease and come to an end
      without further liability or obligation on the part of either party.

        If at any time Landlord shall determine that the proceeds of insurance
      or condemnation awards to be available to Landlord for restoration are
      insufficient for restoration of the Building, Landlord shall provide
      Tenant written notice of such insufficiency and upon receipt of such
      notice, Tenant shall have the right to terminate this Lease by written
      notice to Landlord not later than fifteen (15) days after Tenant's receipt
      of such written notice from Landlord, time being of the essence.  Such
      rights of termination set forth in this Section 12.3 shall be Tenant's
      sole and exclusive remedy at law or in equity for Landlord's failure to
      complete such restoration.

      12.4    AWARD. Landlord shall have and hereby reserves and excepts, and
              ------                                                         
      Tenant hereby grants and assigns to Landlord, all rights to recover for
      damages to the Property and the leasehold interest hereby created, and to
      compensation accrued or hereafter to accrue by reason of such taking,
      damage or destruction and by way of confirming the foregoing, Tenant
      hereby grants and assigns, and covenants with Landlord to grant and assign
      to Landlord, all rights to such damages or compensation. Nothing contained
      herein shall be construed to prevent Tenant from, at its sole cost and
      expense, prosecuting a separate condemnation proceeding with respect to a
      claim for the value of any of Tenant's Removable Property installed in the
      Premises by Tenant at Tenant's expense and for relocation expenses,
      provided that such action shall not affect the amount of compensation
      otherwise recoverable by Landlord from the taking authority.

                                      -37-
<PAGE>
 
                                  ARTICLE XIII
                                  ------------

                                    DEFAULT
                                    -------

      13.1  TENANT'S DEFAULT. (a) If at any time subsequent to the date of this
            -----------------                                                  
      Lease any one or more of the following events (herein referred to as a
      "Default of Tenant") shall happen:

            (i) Tenant shall fail to pay the Basic Rent, Escalation Charges,
       Tenant's Proportionate Share of the Electric Charges, Tenant's
       Proportionate Share of Gas Charges or other sums payable as additional
       charges hereunder when due and such failure shall continue for more than
       five (5) days after written notice thereof from Landlord; or

            (ii) Tenant shall neglect or fail to perform or observe any other
       covenant herein contained on Tenant's part to be performed or observed,
       or Tenant shall desert or abandon the Premises or the Premises shall
       become abandoned (regardless whether the keys shall have been surrendered
       or the rent and all other sums due shall have been paid), and Tenant
       shall fail to remedy the same within thirty (30) days after written
       notice to Tenant specifying such neglect or failure, or if such failure
       is of such a nature that Tenant cannot reasonably remedy the same within
       such thirty (30) day period, Tenant shall fail to commence promptly to
       remedy the same and to prosecute such remedy to completion with diligence
       and continuity; or

            (iii) Tenant's leasehold interest in the Premises shall be taken on
       execution or by other process of law directed against Tenant; or

            (iv) Tenant shall make an assignment for the benefit of creditors or
       shall file a voluntary petition in bankruptcy or shall be adjudicated
       bankrupt or insolvent, or shall file any petition or answer seeking any
       reorganization, arrangement, composition, readjustment, liquidation,
       dissolution or similar relief for itself under any present or future
       Federal, State or other statute, law or regulation for the relief of
       debtors, or shall seek or consent to or acquiesce in the appointment of
       any trustee, receiver or liquidator of Tenant or of all or any
       substantial part of its properties, or shall admit in writing its
       inability to pay its debts generally as they become due; or

            (v) A petition shall be filed against Tenant in bankruptcy or under
       any other law seeking any reorganization, arrangement, composition,
       readjustment, liquidation, dissolution, or similar relief under any

                                      -38-
<PAGE>
 
       present or future Federal, State or other statute, law or regulation and
       shall remain undismissed or unstayed for an aggregate of sixty (60) days
       (whether or not consecutive), or if any debtor in possession (whether or
       not Tenant) trustee, receiver or liquidator of Tenant or of all or any
       substantial part of its properties or of the Premises shall be appointed
       without the consent or acquiescence of Tenant and such appointment shall
       remain unvacated or unstayed for an aggregate of sixty (60) days (whether
       or not consecutive); or

            (vi) If a default of the kind set forth in clauses (i) or (ii) above
       shall occur and if either (a) Tenant shall cure such default within the
       applicable grace period or (b) Landlord shall, in its sole discretion ,
       permit Tenant to cure such default after the applicable grace period has
       expired, and an event which would constitute a similar default if not
       cured within the applicable grace period shall occur more than twice
       within the next 365 days, whether or not such event is cured within the
       applicable grace period;

      then in any such case (1) if such Default of Tenant shall occur prior to
      the Commencement Date, this Lease shall ipso facto, and without further
                                              ---- -----                     
      act on the part of Landlord, terminate, and (2) if such Default of Tenant
      shall occur after the Commencement Date, Landlord may terminate this Lease
      by notice to Tenant, and thereupon this Lease shall come to an end as
      fully and completely as if such date were the date herein originally fixed
      for the expiration of the Term of this Lease, and Tenant will then quit
      and surrender the Premises to Landlord, but Tenant shall remain liable as
      hereinafter provided.

      (b) If this Lease shall be terminated as provided in this Article, or if
      any execution or attachment shall be issued against Tenant or any of
      Tenant's property and such matter is not discharged within thirty (30)
      days whereupon the Premises shall be taken or occupied by someone other
      than Tenant, then Landlord may, without notice, re-enter the Premises,
      either by force, summary proceedings, ejectment or otherwise, and remove
      and dispossess Tenant and all other persons and any and all property from
      the same, as if this Lease had not been made, and Tenant hereby waives the
      service of notice of intention to re-enter or to institute legal
      proceedings to that end.

      (c) In the event of any termination, Tenant shall pay the Basic Rent,
      Escalation Charges, Tenant's Proportionate Share of Electric Charges, Gas
      Charges and other sums payable hereunder up to the time of such
      termination, and thereafter Tenant, until the end of what would have been
      the Term of this Lease in the absence of such termination, and whether or
      not the Premises shall have been relet, shall be liable to Landlord for,
      and shall pay to 

                                      -39-
<PAGE>
 
      Landlord, as liquidated current damages, the Basic Rent, Escalation
      Charges, Tenant's Proportionate Share of the Electric Charges, Tenant's
      Proportionate Share of Gas Charges and other sums which would be payable
      hereunder if such termination had not occurred, less the net proceeds, if
      any, of any reletting of the Premises, after deducting all reasonable
      expenses in connection with such reletting, including, without limitation,
      all repossession costs, brokerage commissions, legal expenses, attorneys'
      fees, advertising, expenses of employees, alteration costs and expenses of
      preparation for such reletting. Tenant shall pay such current damages to
      Landlord monthly on the days which the Basic Rent would have been payable
      hereunder if this Lease had not been terminated. Landlord shall use good
      faith, commercially reasonable efforts to mitigate its damages sustained
      as a result of a termination of this Lease due to a Default of Tenant.

      (d) At any time after such termination, whether or not Landlord shall have
      collected any such current damages, as liquidated final damages and in
      lieu of all such current damages beyond the date of such demand, at
      Landlord's election Tenant shall pay to Landlord an amount equal to the
      excess (discounted to present value), if any, of the Basic Rent,
      Escalation Charges, Tenant's Proportionate Share of the Electric Charges,
      Tenant's Proportionate Share of Gas Charges and other sums as hereinbefore
      provided which would be payable hereunder from the date of such demand
      (assuming that, for the purposes of this paragraph, annual payments by
      Tenant on account of Taxes, Utility Expenses, Tenant's Proportionate Share
      of the Electric Charges, Tenant's Proportionate Share of Gas Charges and
      Operating Expenses would be the same as the payments required for the
      immediately preceding Operating or Tax Year) for what would be the then
      unexpired Term of this Lease if the same had remained in effect, over the
      then fair net rental value of the Premises for the same period.

      (e) In the case of any Default by Tenant, re-entry, expiration and
      dispossession by summary proceeding or otherwise, Landlord may (i) re-let
      the Premises or any part or parts thereof, either in the name of Landlord
      or otherwise, for a term or terms which may at Landlord's option be equal
      to or less than or exceed the period which would otherwise have
      constituted the balance of the Term of this Lease and may grant
      concessions or free rent to the extent that Landlord considers advisable
      and necessary (provided that such concessions are commercially reasonable
      given then current market conditions) to re-let the same and (ii) may make
      such reasonable alterations, repairs and decorations in the Premises as
      Landlord in its sole judgment considers advisable and necessary for the
      purpose of reletting the Premises; and the making of such alterations,
      repairs and decorations shall not operate or 

                                      -40-
<PAGE>
 
      be construed to release Tenant from liability hereunder as aforesaid.
      Landlord shall in no event be liable in any way whatsoever for failure to
      re-let the Premises, or, in the event that the Premises are re-let, for
      failure to collect the rent under such re-letting. 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, or in
      the event of Landlord obtaining possession of the Premises, by reason of
      the violation by Tenant of any of the covenants and conditions of this
      Lease.

      (f) Intentionally Omitted.

      (g) The specified remedies to which Landlord may resort hereunder are not
      intended to be exclusive of any remedies or means of redress to which
      Landlord may at any time be entitled to lawfully, and Landlord may invoke
      any remedy (including the remedy of specific performance) allowed at law
      or in equity as if specific remedies were not herein provided for.

      (h) All costs and expenses incurred by or on behalf of Landlord
      (including, without limitation, attorneys' fees and expenses) in enforcing
      its rights hereunder or occasioned by any Default of Tenant shall be paid
      by Tenant.

      13.2  LANDLORD'S DEFAULT. Landlord shall in no event be in default of the
            -------------------                                                
      performance of any of Landlord's obligations hereunder unless and until
      (i) Landlord shall have unreasonably failed to commence to perform such
      obligation within a period of time reasonably required to commence to
      correct any such default (but in no event later than thirty (30) days),
      after notice by Tenant to Landlord specifying wherein Landlord has failed
      to perform any such obligations or (ii) if timely commenced, Landlord
      shall thereafter promptly fail to diligently prosecute such cure to
      completion.


                                  ARTICLE XIV
                                  -----------

                            MISCELLANEOUS PROVISIONS
                            ------------------------


      14.1  EXTRA HAZARDOUS USE. Tenant covenants and agrees that Tenant will
            --------------------                                             
      not do or permit anything to be done in or upon the Premises, or bring in
      anything or keep anything therein, which shall increase the rate of
      property or liability insurance on the Premises or of the Building above
      the standard rate applicable to premises being occupied for Permitted
      Uses; and Tenant further agrees that, in the event that Tenant shall do
      any of the foregoing, Tenant will promptly pay to Landlord, on 

                                      -41-
<PAGE>
 
      demand, any such increase resulting therefrom, which shall be due and
      payable as an additional charge hereunder.

      14.2  WAIVER. (a) Failure on the part of Landlord or Tenant to complain of
            -------                                                             
      any action or non-action on the part of the other, no matter how long the
      same may continue, shall never be a waiver by Tenant or Landlord,
      respectively, of any of the other's rights hereunder. Further, no waiver
      at any time of any of the provisions hereof by Landlord or Tenant shall be
      construed as a waiver of any of the other provisions hereof, and a waiver
      at any time of any of the provisions hereof shall not be construed as a
      waiver at any subsequent time of the same provisions. The consent or
      approval of Landlord or Tenant to or of any action by the other requiring
      such consent or approval shall not be construed to waive or render
      unnecessary Landlord's or Tenant's consent or approval to or of any
      subsequent similar act by the other.

      (b) No payment by Tenant, or acceptance by Landlord, of a lesser amount
      than shall be due from Tenant to Landlord shall be treated otherwise than
      as a payment on account of the earliest installment of any payment due
      from Tenant under the provisions hereof.  Unless expressly set forth in a
      writing originated by and from Landlord to Tenant, the acceptance by
      Landlord of a check for a lesser amount with an endorsement or statement
      thereon, or upon any letter accompanying such check, that such lesser
      amount is payment in full, shall be given no effect, and Landlord may
      accept such check without prejudice to any other rights or remedies which
      Landlord may have against Tenant.

      14.3    COVENANT OF QUIET ENJOYMENT. Tenant, subject to the terms and
              ----------------------------                                 
      provisions of this Lease, on payment of the Basic Rent and Escalation
      Charges and observing, keeping and performing all of the other terms and
      provisions of this Lease on Tenant's part to be observed, kept and
      performed, shall lawfully, peaceably and quietly have, hold, occupy and
      enjoy the Premises during the term hereof, without hindrance, interruption
      or ejection by any persons lawfully claiming by, through or under Landlord
      to have title to the Premises superior to Tenant; the foregoing covenant
      of quiet enjoyment is in lieu of any other covenant, express or implied.

      14.4  LANDLORD'S LIABILITY. (a) Except as otherwise expressly provided in
            ---------------------                                              
      Section 14.17 and Section 14.26(c) hereof, Tenant specifically agrees to
      look solely to Landlord's then equity interest in the Property at the time
      owned, for recovery of any judgment from Landlord; it being specifically
      agreed that Landlord (original or successor) shall never be personally
      liable for any such judgment, or for the payment of any monetary
      obligation to Tenant. The provision contained in the foregoing sentence is
      not intended to, and shall not, limit any right that Tenant 

                                      -42-
<PAGE>
 
      might otherwise have to obtain injunctive relief against Landlord or
      Landlord's successors in interest, or to take any action not involving the
      personal liability of Landlord (original or successor) to respond in
      monetary damages from Landlord's assets other than Landlord's equity
      interest in the Property.

      (b) Except as otherwise expressly set forth in this Lease, with respect to
      any services or utilities to be furnished by Landlord to Tenant, Landlord
      shall in no event be liable for failure to furnish the same when prevented
      from doing so by Force Majeure, strike, lockout, breakdown, accident,
      order or regulation of or by any governmental authority, or failure of
      supply, or inability by the exercise of reasonable diligence to obtain
      supplies, parts or employees necessary to furnish such services, or
      because of war or other emergency, or for any cause beyond Landlord's
      reasonable control, or for any cause due to any act or neglect of Tenant
      or Tenant's servants, agents, employees, licensees or any person claiming
      by, through or under Tenant; nor shall any such failure give rise to any
      claim in Tenant's favor that Tenant has been evicted, either
      constructively or actually, partially or wholly.

      (c) In no event shall Landlord ever be liable to Tenant for any loss of
      business or any other indirect or consequential damages suffered by Tenant
      from whatever cause.

      (d) With respect to any repairs or restoration which are required or
      permitted to be made by Landlord, the same may be made during normal
      business hours and Landlord shall have no liability for damages to Tenant
      for inconvenience, annoyance or interruption of business arising
      therefrom.

      14.5  NOTICE TO MORTGAGEE OR GROUND LESSOR. After receiving notice from
            -------------------------------------                            
      any person, firm or other entity that it holds a mortgage or a ground
      lease which includes the Premises, no notice from Tenant to Landlord
      alleging any default by Landlord shall be effective unless and until a
      copy of the same is given to such holder or ground lessor (provided Tenant
      shall have been furnished with the name and address of such holder or
      ground lessor), and the curing of any of Landlord's defaults by such
      holder or ground lessor shall be treated as performance by Landlord.

      14.6  ASSIGNMENT OF RENTS AND TRANSFER OF TITLE. With reference to any
            ------------------------------------------                      
      assignment by Landlord of Landlord's interest in this Lease, or the rents
      payable hereunder, conditional in nature or otherwise, which assignment is
      made to the holder of a mortgage on property which includes the Premises,
      Tenant agrees that the execution thereof by Landlord, and the acceptance
      thereof by the holder of such mortgage, shall never be treated as an
      assumption by such holder of any of the obligations of Landlord hereunder
      

                                      -43-
<PAGE>
 
      unless such holder shall, by notice sent to Tenant, specifically otherwise
      elect and that, except as aforesaid, such holder shall be treated as
      having assumed Landlord's obligations hereunder only upon foreclosure of
      such holder's mortgage and the taking of possession of the Premises.

      14.7    RULES AND REGULATIONS. Tenant shall abide by the Rules and
              ----------------------                                    
      Regulations set forth in Exhibit G and any future rules and regulations
      from time to time established by Landlord, it being agreed that such rules
      and regulations will be established and applied by Landlord in a non-
      discriminatory fashion, such that all rules and regulations shall be
      generally applicable to other tenants of the Building of similar nature to
      the Tenant named herein. Landlord agrees to use reasonable efforts to
      insure that any such rules and regulations are uniformly enforced, but
      Landlord shall not be liable to Tenant for violation of the same by any
      other tenant or occupant of the Building, or persons having business with
      them. In the event that there shall be any conflict between such rules and
      regulations and the provisions of this Lease, the provisions of this Lease
      shall control.

      14.8  ADDITIONAL CHARGES. If Tenant shall fail to pay when due any sums
            -------------------                                              
      under this Lease designated or payable as an additional charge, Landlord
      shall have the same rights and remedies as Landlord has hereunder for
      failure to pay Basic Rent.

      14.9  INVALIDITY OF PARTICULAR PROVISIONS. If any term or provision of
            ------------------------------------                            
      this Lease, or the application thereof to any person or circumstance
      shall, to any extent, be invalid or unenforceable, the remainder of this
      Lease, or the application of such term or provision to persons or
      circumstances other than those as to which it is held invalid or
      unenforceable, shall not be affected thereby, and each term and provision
      of this Lease shall be valid and be enforced to the fullest extent
      permitted by Law.

      14.10  PROVISIONS BINDING, ETC. Except as herein otherwise provided, the
             ------------------------                                         
      terms hereof shall be binding upon and shall inure to the benefit of the
      successors and assigns, respectively, of Landlord and Tenant and, if
      Tenant shall be an individual, upon and to his heirs, executors,
      administrators, successors and assigns. Each term and each provision of
      this Lease to be performed by Tenant shall be construed to be both a
      covenant and a condition. The reference contained to successors and
      assigns of Tenant is not intended to constitute a consent to assignment by
      Tenant, but has reference only to those instances in which Landlord may
      later give consent to a particular assignment as required by those
      provisions of Article VI hereof.

      

                                      -44-
<PAGE>
 
      14.11  RECORDING. Tenant agrees not to record this Lease, but each party
             ----------                                                       
      hereto agrees, on the request of the other, to execute a so-called notice
      of lease in form recordable and complying with applicable law and
      reasonably satisfactory to Landlord's attorneys. In no event shall such
      document set forth the rent or other charges payable by Tenant under this
      Lease; and any such document shall expressly state that it is executed
      pursuant to the provisions contained in this Lease, and is not intended to
      vary the terms and conditions of this Lease.

      14.12  NOTICES. Whenever, by the terms of this Lease, notices, consents or
             --------                                                           
      approvals shall or may be given either to Landlord or to Tenant, such
      notices, consents or approvals shall be in writing and shall be sent by
      registered or certified mail, return receipt requested, postage prepaid:

      If intended for Landlord, addressed to Landlord at Landlord's Original
      Address with a copy Addressed to Landlord at 730 Third Avenue, New York,
      New York 10017 Attention: Douglas Lawrence (or to such other address as
      may from time to time hereafter by designated by Landlord by like notice).

      If intended for Tenant, addressed to Tenant, Attn:  Chief Financial
      Officer, at Tenant's Original Address until the Commencement Date and
      thereafter to the Premises with a copy to Richard B. Weitzen, Esq., Lawson
      & Weitzen, 425 Summer Street, Boston, MA 02210 (or to such other address
      or addresses as may from time to time hereafter be designated by Tenant by
      like notice.)

      All such notices shall be effective when deposited in the United States
      Mail within the Continental United States, provided that the same are
      received in ordinary course at the address to which the same were sent.

      14.13  WHEN LEASE BECOMES BINDING. The submission of this document for
             ---------------------------                                    
      examination and negotiation does not constitute an offer to lease, or a
      reservation of, or option for, the Premises, and this document shall
      become effective and binding only upon the execution and delivery hereof
      by both Landlord and Tenant. All negotiations, considerations,
      representations and understandings between Landlord and Tenant are
      incorporated herein and this Lease expressly supersedes any proposals or
      other written documents relating hereto. This Lease may be modified or
      altered only by written agreement between Landlord and Tenant, and no act
      or omission of any employee or agent of Landlord shall alter, change or
      modify any of the provisions hereof.

      14.14  PARAGRAPH HEADINGS. The paragraph headings throughout this
             -------------------                                       
      instrument are for convenience and reference only, and the words contained
      therein shall in no way be held to 

                                      -45-
<PAGE>
 
      explain, modify, amplify or aid in the interpretation, construction, or
      meaning of the provisions of this Lease.

      14.15 RIGHTS OF MORTGAGEE OR GROUND LESSOR. This Lease shall be
            -------------------------------------                    
      subordinate to any mortgage or ground lease from time to time encumbering
      the Premises, whether executed and delivered prior to or subsequent to the
      date of this Lease, if the holder of such mortgage or ground lease shall
      so elect. If this Lease is subordinate to any mortgage or ground lease and
      the holder thereof (or successor) shall succeed to the interest of
      Landlord, at the election of such holder (or successor) Tenant shall
      attorn to such holder and this Lease shall continue in full force and
      effect between such holder (or successor) and Tenant. Tenant agrees to
      execute such instruments of subordination or attornment in confirmation of
      the foregoing agreement as such holder may request.

           Notwithstanding anything to the contrary contained in this Section
      14.15, Tenant shall not be required to subordinate this Lease to any
      mortgage or to the lien of any mortgage or sale and leaseback, nor shall
      the subordination provided herein be self-operative unless the holder of
      such mortgage or ground lease, as the case may be, shall enter into an
      agreement with Tenant, recordable in form, to the effect  that in the
      event of foreclosure of, or similar action taken under, such mortgage or
      ground lease, this Lease shall not be terminated or Tenant's occupancy
      disturbed by such mortgageholder or ground lessor or anyone claiming under
      such mortgageholder or ground lessor, as the case may be, so long as
      Tenant shall not be in default under this Lease.  The form of any such
      agreement shall be the form as reasonably required by any such mortgagee
      or ground lessor.

      14.16  STATUS REPORT. Recognizing that both parties may find it necessary
             --------------                                                    
      to establish to third parties, such as accountants, banks, mortgagees,
      ground lessors, or the like, the then current status of performance
      hereunder, either party, on the request of the other made from time to
      time, will promptly furnish to Landlord, or the holder of any mortgage or
      ground lease encumbering the Premises, or to Tenant, as the case may be, a
      statement of the status of any matter pertaining to this Lease, including,
      without limitation, acknowledgment that (or the extent to which) each
      party is in compliance with its obligations under the terms of this Lease.

       14.17  SECURITY DEPOSIT.  Concurrently with the execution and delivery of
              -----------------                                                 
       this Lease, Tenant shall deposit 1/3 of the Security Deposit specified in
       Section 1.2 hereof with Landlord.  Not later than the date which is ten
       (10) days after the date Landlord shall advise Tenant that the Landlord's
       Work is 50% complete, Tenant shall deposit an additional 1/3 of the
       Security Deposit with Landlord.  The 

                                      -46-
<PAGE>
 
       remaining 1/3 of the Security Deposit shall be deposited with Landlord on
       the date that Tenant shall occupy the Premises and as a condition to
       Tenant's occupancy of the Premises for the conduct of its business
       notwithstanding that the Commencement Date as defined in Article IV
       hereof may have occurred. Landlord shall have the same rights and
       remedies against Tenant for Tenant's failure to timely deposit any
       installment of the Security Deposit with Landlord as Landlord has against
       Tenant for failure to pay Basic Rent when due. Landlord shall hold the
       same throughout the Term of this Lease as security for the performance by
       Tenant of all obligations on the part of Tenant hereunder. Landlord shall
       have the right from time to time without prejudice to any other remedy
       Landlord may have on account thereof, to apply such deposit, or any part
       thereof, to Landlord's damages arising from, or to cure, any Default of
       Tenant. If Landlord shall so apply any or all of such deposit, Tenant
       shall immediately deposit with Landlord the amount so applied to be held
       as security hereunder. There then existing no Default of Tenant, Landlord
       shall return the deposit, or so much thereof as shall theretofore not
       been applied in accordance with the terms of this Section 14.17, to
       Tenant on the expiration or earlier termination of the Term of this Lease
       and surrender of possession of the Premises by Tenant to Landlord at such
       time. Landlord shall deposit the Security Deposit in a separate federally
       insured savings account with a bank or financial institution selected by
       Landlord. All interest accrued in such account less a 1% administrative
       fee payable to Landlord shall be paid to Tenant at the end of each Lease
       Year upon the written request of Tenant. The one percent fee shall be
       earned, paid to and retained by Landlord on an annual basis.

         If Landlord conveys Landlord's interest under this Lease, the deposit,
       or any part thereof not previously applied, may be turned over by
       Landlord to Landlord's grantee, and, if so turned over, Tenant agrees to
       look solely to such grantee for proper application of the deposit in
       accordance with the terms of this Section 14.17, and the return thereof
       in accordance therewith. To the extent that the deposit or any part
       thereof not previously applied, has not been turned over by Landlord to
       Landlord's grantee or successor in interest, Tenant may, in addition to
       any other remedies it may have at law or in equity, look to Landlord for
       the proper application of the deposit in accordance with the terms of
       this Section 14.17, and the return thereof in accordance therewith.  The
       provisions of Section 14.4(a) shall not apply to an action brought
       against Landlord arising out of Landlord's failure to return the deposit
       to Tenant as and when required hereunder nor to Landlord's failure to
       deliver same to its grantee or successor  in interest and Tenant may seek
       to recover same from other assets of Landlord.  The holder of 

                                      -47-
<PAGE>
 
       a mortgage shall not be responsible to Tenant for the return or
       application of any such deposit, whether or not it succeeds to the
       position of Landlord hereunder, unless such deposit shall have been
       received in hand by such holder.

       The amount of the Security Deposit shall be reduced over time as follows:

         (a) beginning on the date of execution and delivery of this Lease by
       Tenant through the last day of the 12th full calendar month immediately
       following the Commencement Date, the amount of the Security Deposit shall
       be $229,000.00.

         (b) During the six (6) full calendar months immediately following the
       period described in (a) above, the amount of the Security Deposit shall
       be in the amount of $150,000.00.

         (c) For the period beginning immediately following expiration of the
       Period described in (b) through the last day of the Term of the Lease,
       the amount of the Security Deposit shall be $100,000.00.

      14.18  REMEDYING DEFAULTS. Landlord shall have the right, but shall not be
             -------------------                                                
      required, to pay such sums or to do any act which requires the expenditure
      of monies which may be necessary or appropriate by reason of the failure
      or neglect of Tenant to perform any of the provisions of this Lease, and
      in the event of the exercise of such right by Landlord, Tenant agrees to
      pay to Landlord forthwith upon demand all such sums, together with
      interest thereon at a rate equal to 3% over the prime rate in effect from
      time to time at the First National Bank of Boston (but in no event less
      than 18% per annum), as an additional charge. Any payment of Fixed Rent,
      Escalation Charges or other sums payable hereunder not paid when due
      shall, at the option of Landlord, bear interest at a rate equal to 3% over
      the prime rate in effect from time to time at the First National Bank of
      Boston (but in no event less than 18% per annum) from the due date thereof
      and shall be payable forthwith on demand by Landlord, as an additional
      charge.

      14.19  HOLDING OVER. Any holding over by Tenant after the expiration of
             -------------                                                   
      the Term of this Lease shall be treated as a daily tenancy at sufferance
      at a rate equal to the then fair rental value of the Premises but in no
      event less than 150% of the sum of (i) Basic Rent and (ii) Escalation
      Charges in effect on the expiration date plus all Tenant's Proportionate
      Share of the Electric Charges and Tenant's Proportionate Share of Gas
      Charges. Tenant shall also pay to Landlord all damages, direct and/or
      indirect (including any loss of a tenant or rental income), sustained by

                                      -48-
<PAGE>
 
      reason of any such holding over. Otherwise, such holding over shall be on
      the terms and conditions set forth in this Lease as far as applicable.

      14.20  WAIVER OF SUBROGATION. Insofar as, and to the extent that, the
             ----------------------                                        
      following provision shall not make it impossible to secure insurance
      coverage obtainable from responsible insurance companies doing business in
      the locality in which the Property is located (even though extra premium
      may result therefrom) Landlord and Tenant mutually agree that any property
      damage insurance carried by either shall provide for the waiver by the
      insurance carrier of any right of subrogation against the other, and they
      further mutually agree that, with respect to any damage to property, the
      loss from which is covered by insurance then being carried by them,
      respectively, the one carrying such insurance and suffering such loss
      releases the other of and from any and all claims with respect to such
      loss to the extent of the insurance proceeds paid with respect thereto.

      14.21  SURRENDER OF PREMISES. Upon the expiration or earlier termination
             ----------------------                                           
      of the Term of this Lease, Tenant shall peaceably quit and surrender to
      Landlord the Premises in neat and clean condition and in good order,
      condition and repair, together with all alterations, additions and
      improvements which may have been made or installed in, on or to the
      Premises prior to or during the Term of this Lease, excepting only
      ordinary wear and use and damage by fire or other casualty for which,
      under other provisions of this Lease, Tenant has no responsibility of
      repair and restoration. Tenant shall remove all of Tenant's Removable
      Property and, to the extent specified by Landlord, all alterations and
      additions made by Tenant after the Commencement Date which Landlord shall
      designate for removal by Tenant at the time of Landlord granting its
      consent to the making or installation of the applicable alteration or
      improvement; and shall repair any damage to the Premises or the Building
      caused by such removal. Any Tenant's Removable Property which shall remain
      in the Building or on the Premises after the expiration or termination of
      the Term of this Lease shall be deemed conclusively to have been
      abandoned, and either may be retained by Landlord as its property or may
      be disposed of in such manner as Landlord may see fit, at Tenant's sole
      cost and expense.

14.22 INTENTIONALLY OMITTED.
      ----------------------

      14.23    INTENTIONALLY OMITTED.
               ----------------------

      14.24  BROKERAGE. Tenant warrants and represents that Tenant has dealt
             ----------                                                     
      with no broker in connection with the consummation of this Lease other
      than Lynch, Murphy, Walsh & Partners and Cushman & Wakefield (collectively
      the "Broker"), and, 

                                      -49-
<PAGE>
 
      in the event of any brokerage claims against Landlord predicated upon
      prior dealings with Tenant, Tenant agrees to defend the same and indemnify
      Landlord against any such claim (except any claim by the Broker which
      shall be paid by Landlord in accordance with its arrangements with the
      Broker).

      14.25  SPECIAL TAXATION PROVISIONS.  Landlord shall have the right at any
             ----------------------------                                      
      time and from time to time, to unilaterally amend the provisions of this
      Lease if Landlord is advised by its Counsel that all or any portion of the
      monies paid by Tenant to Landlord hereunder are, or may be deemed to be,
      unrelated business income within the meaning of the United States Internal
      Revenue Code, or regulation issued thereunder, and Tenant agrees that it
      will execute all documents or instruments necessary to effect such
      amendment or amendments, provided that no such amendment shall result in
      Tenant having to pay in the aggregate more money on account of its
      occupancy of the demised premises under the provisions of this Lease as so
      amended and provided further, that no such amendment or amendments shall
      result in Tenant receiving under the provisions of this Lease less
      services than it is entitled to receive nor services of a lesser quality.
      Anything contained in the foregoing provisions of this Lease (including,
      without limitation, Article VI hereof) to the contrary notwithstanding,
      neither Tenant nor any other person having an interest in the possession,
      use, occupancy or utilization of the Premises, shall enter into any lease,
      sublease, license, concession or other agreement for use, occupancy,
      utilization of space in the Premises which provides for rental or other
      payment for such use, occupancy or utilization of space, in whole or in
      part, on the net income or profits derived by any person from the Premises
      leased, used, occupied or utilized (other than an amount based on a fixed
      percentage or percentage of receipts for sales) and any such recorded
      lease, sublease, license, concession or other agreement shall be
      absolutely void and ineffective as a conveyance of any right or interest
      in the possession, use, occupancy or utilization of any part of the
      Premises.

      14.26  HAZARDOUS MATERIALS.  (a) Tenant shall not (either with or without
             --------------------                                              
      negligence) cause or permit the escape, disposal, release or threat of
      release of any biologically or chemically active or other Hazardous
      Materials (as said term is hereafter defined) on, in, upon or under the
      Property or the Premises.  Tenant shall not allow the generation, storage,
      use or disposal of such Hazardous Materials on the Property, nor allow to
      be brought into the Property any such Hazardous Materials.  Hazardous
      Materials shall include, without limitation, any material or substance
      which is (i) petroleum, (ii) asbestos, (iii) designated as a "hazardous
      substance" pursuant to Section 311 of the Federal Water Pollution Control
      Act, 33 U.S.C. 

                                      -50-
<PAGE>
 
      Section 1251 et seq. (33 U.S.C. Section 1321) or listed pursuant to
      Section 307 of the Federal Water Pollution Control Act (33 U.S.C. Section
      1317), (iv) defined as a "hazardous waste" pursuant to Section 1004 of the
      Resource Conservation and Recovery Act, 42 U.S.C. Section 6901 et seq. (42
      U.S.C. Section 6903), (v) defined as a "hazardous substance" pursuant to
      Section 101 of the Comprehensive Environmental Response, Compensation, and
      Liability Act, 42 U.S.C. Section 9601 et seq. (42 U.S.C. Section 9601), as
      amended ("CERCLA"), or (vi) defined as "oil" or a "hazardous waste", a
      "hazardous substance", a "hazardous material" or a "toxic material" under
      any other law, rule or regulation applicable to the Property, including,
      without limitation, Chapter 21E of the Massachusetts General Laws, as
      amended ("Chapter 21E"). If any lender or governmental agency shall ever
      require testing to ascertain whether or not there has been any release of
      Hazardous Materials, then the reasonable costs thereof shall be reimbursed
      by Tenant to Landlord upon demand as additional charges but only if such
      testing determines that such release or the presence of Hazardous
      Materials is or was the result of the acts or omissions of Tenant. In
      addition, Tenant shall execute affidavits, representations and the like,
      from time to time, at Landlord's request concerning Tenant's best
      knowledge and belief regarding the presence of Hazardous Materials on the
      Premises. In all events, Tenant shall indemnify and save Landlord harmless
      from and against any and all loss, claims, liability, costs, expenses,
      reasonable attorneys fees and damages of every nature from any release or
      threat of release or the presence or existence of Hazardous Materials on
      the Premises occurring while Tenant is in possession, or elsewhere on the
      Property if caused, in whole or in part, by Tenant or persons acting under
      Tenant. The within covenants and indemnity shall survive the expiration or
      earlier termination of the Term of this Lease. Landlord expressly reserves
      the right to enter the Premises to perform regular inspections.

      (b) Landlord agrees to indemnify and save harmless Tenant from and against
      all claims, loss, liability, costs, expenses (including, without
      limitation, reasonable attorneys' fees as referred to in paragraph (c) of
      this Section) and damages of whatever nature arising from any release or
      threat of release of the presence or existence of Hazardous Materials on
      the Premises, or elsewhere on the Property, or on properties other than
      the Property, if caused in whole or in part by any person or entity other
      than Tenant or persons acting under Tenant ("Non-Tenant Release")
      including without limitation:  (i) Hazardous Waste presently existing in,
      on, or under the Property; (ii) any future release or disposal, or threat
      of release or disposal, of Hazardous Waste in, on or under the Property
      resulting from a Non-Tenant Release; (iii) Hazardous Waste presently
      existing in, on, or under properties other than the Property and which
      migrate, or 

                                      -51-
<PAGE>
 
     in the future migrate or may migrate, in, on, or under the Property; (iv)
      any future release or disposal, or threat of release or disposal, of
      Hazardous Waste in, on, or under properties other than the Property and
      which migrate, or in the future migrate or may migrate, in, on, or under
      the Property resulting from a Non-Tenant Release; (v) the cleanup and/or
      removal of any Hazardous Waste from the Property or any other property
      resulting from a Non-Tenant Release; (vi) the performance of any response
      or remediation action, and any response action or remediation costs, fees,
      expenses, charges, or penalties ordered, assessed, exacted, levied,
      imposed, or required by the United States of America, the Commonwealth of
      Massachusetts or the Town of Burlington, or any compliance with the
      CERCLA, Chapter 21E, the Massachusetts Contingency Plan (310 C.M.R.
      40.0000), or other federal, state or local laws, by-laws, rules or
      regulations that apply to response actions, all as the same may be amended
      from time to time, resulting from a Non-Tenant Release; (vii) any
      administrative or judicial enforcement action brought by the United States
      of America, the Commonwealth of Massachusetts or the Town of Burlington
      (including, without limitation, claims regarding contamination-related
      damage to natural resources) resulting from a Non-Tenant Release; and
      (viii) any personal injury or property damage claims or actions brought by
      third parties resulting from a Non-Tenant Release. It is agreed and
      understood that except as otherwise expressly provided in this Section
      (b), the provisions of Section 14.4 of this Lease shall be applicable to
      all of the matters described in this Section (b).

      (c) Landlord agrees to promptly reimburse Tenant for any and all
      reasonable attorneys' fees and court  costs (up to the aggregate amount of
      Twenty-Five Thousand ($25,000.00) Dollars) incurred by Tenant in
      connection with any claim or matter relating to, or in connection with,
      any Non-Tenant Release including, without limitation, any of the matters
      referred to in paragraph (b) of this Section.  The provisions of Section
      14.4(a) shall not apply with respect to any action brought by Tenant
      against Landlord for reimbursement of the fees, expenses and costs
      referred to in this paragraph (c).

      14.27  GOVERNING LAW. This Lease shall be governed exclusively by the
             --------------                                                
      provisions hereof and by the laws of the Commonwealth of Massachusetts, as
      the same may from time to time exist.

       14.28  OPTION TO EXTEND.   (a) Tenant shall have the right and option,
              -----------------                                              
       which said option and right shall not be severed from this Lease or
       separately assigned, mortgaged or transferred, to extend the Initial Term
       for one (1) additional consecutive period of three (3)years (hereinafter
       referred to as the "Extension Period"), provided that (a) Tenant shall
       give Landlord notice of 

                                      -52-
<PAGE>
 
       Tenant's exercise of such option at least thirteen (13) full calendar
       months prior to the expiration of the Initial Term (b) there shall exist
       no Default of Tenant arising under any of the terms and provisions of the
       Lease on the part of Tenant to be performed or observed both at the time
       of giving the applicable notice and the commencement of the Extension
       Period (c) the original Tenant named in this Lease or any assignee of
       Tenant permitted pursuant to Article VI shall be in occupancy of the
       Premises both at the time of giving such notice and upon commencement of
       the applicable Extension Period. Except for the amount of Basic Rent
       (which is to be determined as hereinafter provided), all the terms,
       covenants, conditions, provisions and agreements in the Lease contained
       shall be applicable to the additional period through which the Term of
       this Lease shall be extended as aforesaid, except that there shall be no
       further option to extend the Term nor shall Landlord be obligated to make
       or pay for any improvements to the Premises nor pay any inducement
       payments or allowances of any kind or nature. If Tenant shall give notice
       of its exercise of such option to extend in the manner and within the
       time period provided aforesaid then, subject to the provisions of the
       remainder of this Section 14.28, the Term of this Lease shall be extended
       upon the giving of each such notice without the requirement of any
       further attention on the part of either Landlord or Tenant. Landlord
       hereby reserves the right, exercisable by Landlord in its sole
       discretion, to waive (in writing) any condition precedent set forth in
       clauses (a), (b) or (c) above.

           If Tenant shall fail to give timely notice of the exercise of such
       option as aforesaid, Tenant shall have no right to extend the Term of
       this Lease, time being of the essence of the foregoing provisions.  Any
       termination of this Lease Agreement shall terminate the rights hereby
       granted Tenant.

          (b) Fair Market Value.  The Basic Rent per annum payable  during the
              -----------------                                               
       Extension Period shall be 95% of the Fair Market Rental Value (as said
       term is hereinafter defined) as of commencement of the Extension Period,
       but in no event less than the Basic Rent plus Escalation Charges payable
       for and with respect to the 12 month period immediately preceding the
       Extension Period.  "Fair Market Rental Value" shall be computed as of the
       date in question at the then current annual rental charges, including
       provisions for subsequent increases and other adjustments, for extensions
       of existing leases then being negotiated or executed for comparable space
       located in comparable buildings in Burlington, Massachusetts .  In
       determining Fair Market Rental Value, the following factors, among
       others, shall be taken into account and given effect:  size of the
       premises, escalation charges then payable 

                                      -53-
<PAGE>
 
       under the Lease, location of the premises, location of the building,
       allowances or lack of allowances (if any) leasing concessions (if any),
       age and condition of improvements and lease term. In no event shall the
       Basic Rent payable with respect to the Extension Period be less than the
       Basic Rent plus Escalation Charges payable during the last Year of the
       Initial Term.

          (c) Dispute as to Fair Market Rental Value.  Landlord shall initially
              --------------------------------------                           
       designate the Fair Market Rental Value and shall furnish data in support
       of such designation.  If Tenant disagrees with Landlord's designation of
       the Fair Market Rental Value, Tenant shall have the right, by written
       notice given to Landlord within fifteen (15) days after Tenant has been
       notified of Landlord's designation, to submit such Fair Market Rental
       Value to arbitration as follows:  Fair Market Rental Value shall be
       determined by impartial arbitrators who shall be licensed real estate
       appraisers who are members of the Massachusetts or American Society of
       Real Estate Appraisers with at least ten (10) years of experience (a
       "Qualified Appraiser"), one to be chosen by Landlord, one to be chosen by
       Tenant, and a third to be selected, if necessary, as below provided.  The
       unanimous written decision of the two first chosen, without selection and
       participation of a third arbitrator, or otherwise, the written decision
       of a majority of three arbitrators chosen and selected as provided below,
       shall be conclusive and binding upon Landlord and Tenant.  If the
       designations of all three arbitrators are different in amount, then the
       Fair Market Rental Value shall be deemed to be the average of the two
       designations that are the closest in amount.

          Landlord and Tenant shall each notify the other of its chosen
       arbitrator within ten (10) days following the call for arbitration and,
       if such two arbitrators shall not have reached a unanimous decision
       within twenty (20) days after their designation, they shall so notify the
       then president of the Boston Bar Association and request him to select an
       impartial third arbitrator, who shall be , a Qualified Appraiser to
       determine Fair Market Rental Value as herein defined.  The arbitrators
       shall advise the parties of their determination by written notice (a
       "Fair Market Value Designation") no later than the date which is ten (10)
       full calendar months prior to the commencement of the Extension Period.

            (d) Upon receipt of such Fair Market Value Designation, and if
       Landlord and Tenant have not otherwise agreed upon the Fair Market Rental
       Value Designation, then Tenant shall have the right to revoke its
       exercise of the Extension Option by written notice to Landlord (an
       "Option Rent Revocation") given to Landlord not later than the date which
       is nine (9) full calendar months prior to expiration of the Initial Term.
       Failure of Tenant to give 

                                      -54-
<PAGE>
 
       Landlord an Option Rent Revocation in the time and manner herein
       specified, time being of the essence shall be deemed a waiver of Tenant's
       right to revoke its exercise of the applicable Option to Extend and
       Tenant shall be deemed to have (i) accepted the determination of the Fair
       Market Rental Value by the Arbitrators as set forth in the Fair Market
       Value Designation and (ii) exercised and not revoked its option to extend
       for the applicable Extension Period. If Tenant shall provide Landlord
       with a timely Option Rent Revocation, Tenant shall promptly reimburse
       Landlord for all costs and expenses sustained or incurred by Landlord for
       the Qualified Appraisers.

       14.29  AUTOMATIC EXPANSION OF PREMISES.  (a) There is certain space,
              --------------------------------                             
       identified on Exhibit A as the "First Expansion Space" and the "Second
       Expansion Space" (the First Expansion Space and the Second Expansion
       Space are sometimes hereafter collectively referred to as the "Expansion
       Space").  The Expansion Space is presently occupied by another tenant
       ("NEMRB").  In the event that NEMRB shall remain in occupancy of the
       Expansion Space beyond October 31, 1996, Landlord, at its sole cost and
       expense, shall promptly commence summary process proceedings to cause the
       removal or eviction of NEMRB from the Expansion Space (and shall
       thereafter diligently pursue such action to completion) upon expiration
       of the Term of the NEMRB Lease.  Notwithstanding anything contained in
       this Section 14.29 to the contrary, in the event that NEMRB shall not
       vacate the Expansion Space on or before January 31, 1997, Tenant may, at
       its option, by written notice to Landlord on or before February 5, 1997
       terminate the provisions of this Section 14.29 (the "NEMRB Termination
       Right") and all of Landlord and Tenant's rights and obligations under
       this Lease as they pertain to the Expansion Space (and only as they
       pertain to the Expansion Space), which termination shall be effective as
       of the date of such notice.  Failure of Tenant to give Landlord such
       termination notice within the time and manner herein specified shall be
       deemed a waiver of Tenant's NEMRB Termination Right.  Upon NEMRB vacating
       the Expansion Space, Landlord shall commence Landlord's Expansion Work
       (as hereafter defined) in the applicable portion(s) of the Expansion
       Space.

          Landlord and Tenant acknowledge and agree that their preference would
       be to have Tenant occupy and to include within the Premises all of the
       Expansion Space as of the Expansion Commencement Date.  However, Landlord
       may enter into a leasing arrangement with another tenant of an adjacent
       property owned by Landlord, which tenant is known as Workgroup Solutions,
       Inc. ("Workgroup") pursuant to which Workgroup would lease the Second
       Expansion Space through October 31, 1997.  In the event that Landlord
       shall enter into a leasing arrangement for the Second Expansion Space
       with Workgroup, Tenant shall first occupy 

                                      -55-
<PAGE>
 
       the First Expansion Space on the First Expansion Commencement Date upon,
       subject to and in accordance with the terms and provisions of Section
       14.29(c) hereof and shall thereafter occupy the Second Expansion Space on
       the Second Expansion Commencement Date upon, subject to and in accordance
       with the provisions of Section 14.29(d) hereof. If Landlord shall not
       enter into such an arrangement with Workgroup, Tenant shall occupy the
       entire Expansion Space upon, subject to and in accordance with the
       provisions of Section 14.29(b) hereof, all as hereafter set forth. Upon
       determining whether or not Workgroup will be occupying the Second
       Expansion Space as aforesaid, Landlord shall promptly provide Tenant with
       written notice of its decision and arrangements with Workgroup (a

                                      -56-
<PAGE>
 
       "Workgroup Notice"), if any, as to the Second Expansion Space.  In any
       and all events, Landlord shall give Tenant a Workgroup Notice on or
       before January 1, 1996.

          For purposes of preparing, as applicable, the Expansion Cost
       Statement, the First Expansion Cost Statement and the Second Expansion
       Cost Statement pursuant to Section 14.29(b), 14.29(c) and 14.29(d) hereof
       or any revisions thereto, Landlord shall solicit three (3) bids from each
       of the major trades (two names designated by Landlord, one designated by
       Tenant) and Landlord shall select and designate the lowest qualified
       bidder and bid in each such trade in rendering such statements or any
       modifications thereto.  Landlord shall notify Tenant in advance of
       soliciting bids that Tenant's designee is not a qualified bidder and the
       reasons therefor.

          (b) If the provisions of this Section 14.29 shall not be terminated
       pursuant to Section 14.29(a) hereof and provided that Landlord shall give
       Tenant a Workgroup Notice indicating that Workgroup will not be leasing
       the Second Expansion Space then, Tenant shall lease the entire Expansion
       Space from Landlord pursuant to this Section 14.29(b) at one time (rather
       than in two phases) and effective as of the Expansion Commencement Date
       (as hereafter defined), the entire Expansion Space shall be added to and
       included within the "Premises" for all purposes under the Lease without
       the requirement of any further attention on the part of either Landlord
       or Tenant and in such case, effective as of the Expansion Commencement
       Date, this Lease shall be deemed amended in the following respects (and
       if requested by Landlord, Tenant shall promptly execute and deliver an
       amendment to this Lease reflecting the matters herein set forth):

          (i) The Premises and the Premises Rentable Area shall be deemed
       amended to include the entire Expansion Space within the Premises and the
       Premises and the Premises Rentable Area shall be increased by 9,299
       rentable square feet included in the Expansion Space to be and consist of
       a total of 39,482 rentable square feet for all purposes under this Lease;

          (ii) Basic Rent per annum shall be increased by an annual amount (the
       "Expansion Rent") equal to the Per Square Foot Rent Rate (as said term is
       hereinafter defined) from time to time applicable multiplied by the
       number of rentable square feet contained in the Expansion Space (9,299);

          (iii) the Escalation Factor shall be deemed increased to be 100%  for
       all purposes and, accordingly, Tenant's monthly and annual payments on
       account of the Escalation Charges shall be increased to reflect the
       increase in the Premises by virtue of the addition of the Expansion
       Space;

                                      -57-
<PAGE>
 
          (iv) The increases in Basic Rent and Escalation Charges as determined
       pursuant to subparagraphs (i) through (iii) above shall become effective
       on the Expansion Commencement Date.

          As used herein, the terms Per Square Foot Rent Rate and Expansion Rent
       shall be in the following amounts during the following periods of the
       Initial Term of this Lease:
<TABLE>
<CAPTION>
 
 
          Period             Per Square Foot            Expansion Rent
---------------------------     Rent Rate     ----------------------------------
                             ---------------
 
<S>                          <C>              <C>
Expansion Commence-ment               $10.28  $95,593.72 per annum ($7,966.14
 Date through June 30, 1997                   per month)
 
July 1, 1997 through June             $10.53  $97,918.47 per annum ($8,159.87
 30, 1998                                     per month)
 
July 1, 1998 through June             $10.78  $100,243.22 per annum ($8,353.60
 30, 1999                                     per month)
 
July 1, 1999 through the              $11.03  $102,567.97 per annum ($8,547.33
 last day of the Initial                      per month)
 Term
 
</TABLE>

                 As used herein, the term "Expansion Commencement Date" shall be
       the last to occur of (i) January 31, 1997 (the "Expansion Construction
       Completion Date"), or (ii) the day following the date on which the
       Expansion Space is "ready for occupancy" as hereafter provided.
       Notwithstanding the foregoing, if Tenant's personnel shall occupy all or
       any part of the Expansion Space for the conduct of its business prior to
       the Expansion Commencement Date, such date shall for all purposes of this
       Lease be the Expansion Commencement Date.  The Tenant shall, upon demand
       of the Landlord, execute a certificate confirming the Expansion
       Commencement Date as it is determined in accordance with the provisions
       of this Section 14.29(b)

               On or before July 31, 1996, Tenant shall deliver to Landlord a
       Space Plan together with certain written specifications (hereafter the
       "Expansion Space Plan") depicting installations and improvements
       necessary to prepare the Expansion Space for Tenant's occupancy.  Upon
       receipt of the Expansion Space Plan from Tenant, Landlord shall promptly
       cause its architects and engineers to prepare final working drawings and
       specifications 

                                      -58-
<PAGE>
 
       reflecting the work and improvement shown on the Expansion Space Plan
       (the "Proposed Expansion Plans"). Upon completion of such Proposed
       Expansion Plans, Landlord shall submit same to Tenant for review and
       approval together with a statement from Landlord (the "Expansion Cost
       Statement") with respect to whether or not the costs of all work,
       materials, permit fees, architectural fees and engineering fees (the
       "Cost of Expansion Work") necessary to prepare such Proposed Expansion
       Plans and to complete the improvements shown thereon exceed $69,747.50
       (the "Expansion Allowance"). Such costs set forth in the Expansion Cost
       Statement which are in excess of the Expansion Allowance (the "Expansion
       OBS Costs") shall be borne by Tenant in the manner hereafter specified.
       Tenant shall either approve or reject such Proposed Expansion Plans
       within ten (10) days after receipt from Landlord. Tenant hereby agrees to
       approve and shall not unreasonably withhold or delay its approval of such
       Proposed Expansion Plans provided that they are substantially in
       compliance with those matters set forth in the Expansion Space Plan.
       Failure of Tenant to object to any aspect of such Proposed Expansion
       Plans within the time and manner provided above shall be deemed an
       approval of such Proposed Expansion Plans and authorization for Landlord
       to proceed with Landlord's Expansion Work in accordance therewith. Tenant
       shall have the right to consult with Landlord's architect for purposes of
       review and approval of Proposed Expansion Plans and review of the
       Expansion Cost Statement. Landlord and Tenant shall each cooperate with
       the architect in connection with the preparation, review and approval of
       Proposed Expansion Plans and the finalization of Tenant's Expansion
       Plans.

               If Tenant shall reject any aspect of such Proposed Expansion
       Plans within the time and manner provided above, Landlord shall promptly
       make such revisions to the Proposed Expansion Plans as may be necessary
       so as to bring them into substantial compliance with the matters set
       forth in the Expansion Space Plan and shall provide Tenant with a revised
       Expansion Cost Statement based on the cost of completing the work shown
       on the revised Proposed Expansion Plans.  Tenant shall approve or reject
       such revised Proposed Expansion Plans within ten (10) days after receipt.
       Tenant shall not unreasonably withhold or delay its approval to such
       revised Proposed Expansion Plans provided that they substantially comply
       with the Expansion Space Plan.  Failure of Tenant to respond within the
       time and manner herein provided shall be deemed a waiver of such right by
       Tenant and Tenant shall be deemed to have approved such revised Proposed
       Expansion Plans as submitted by Landlord and to have authorized Landlord
       to proceed with Landlord's Expansion Work in accordance therewith.  Upon
       approval by both Landlord and Tenant, such working drawings and
       

                                      -59-
<PAGE>
 
       specifications shall be deemed to be Tenant's Expansion Plans for all
       purposes under this Lease.  The OBS Costs described in such revised
       Expansion Cost Statement shall, for all purposes hereunder, be deemed to
       be "Expansion OBS Costs".

                 To the extent that Tenant shall request any changes or
       modifications to Tenant's Expansion Plans (and provided that Landlord
       shall approve such changes, which approval will not be unreasonably
       withheld or delayed), Tenant shall pay the additional cost of completing
       Landlord's Expansion Work resulting from such changes to Landlord as
       additional Expansion OBS Costs hereunder as follows:  50% of costs shall
       be paid at the time of approval of such change and 50% shall be paid on
       the Expansion Commencement Date and Landlord's approval of any such
       proposed changes shall be accompanied by a Statement of Expansion OBS
       Costs and Tenant's Delay, if any, which will result from such changes.
       Similarly, all Expansion OBS Costs shall be paid in the same manner, 50%
       prior to Landlord commencing work and 50% on the Expansion Commencement
       Date.  Landlord and Tenant shall, if requested by the other, execute a
       work letter confirming such excess costs prior to the time Landlord shall
       be required to commence work.  Upon final approval of any such revised
       Tenant's Expansion Plans by Landlord and Tenant, Landlord shall promptly
       proceed with such Landlord's Expansion Work.

            The Expansion Space shall be deemed "ready for occupancy" on the
       first Business Day (the "Expansion Substantial Completion Date")
       following written notice to Tenant that Landlord's Expansion Work has
       been completed except for items of work (and, if applicable, adjustment
       of equipment and fixtures) which can be completed after occupancy has
       been taken without causing substantial interference with Tenant's use of
       the Expansion Space (i.e., so called "punch-list" items.  Landlord's
       notice shall be accompanied by Landlord's Architect's certificate of
       completion (certified to Landlord and Tenant) of Landlord's Expansion
       Work and, if applicable, a C of O (as defined in Section 4.2(b) for the
       Expansion Space.  It is agreed and understood that a so-called
       "conditional" or "temporary" Certificate of Occupancy or Occupancy Permit
       shall be deemed to satisfy the C of O requirement of the immediately
       preceding sentence provided that the only condition to issuance of a
       Final C of O then outstanding pertains solely to matters or work which
       are the responsibility of the Tenant rather than the obligation or
       responsibility of Landlord under this Lease.  Tenant shall provide
       Landlord with a final punch list (the "Expansion Punch-list") as to the
       status of completion of Landlord's Expansion Work within ten (10) days
       after delivery to Tenant of the aforementioned notice that the Expansion
       Space is "ready for occupancy." 

                                      -60-
<PAGE>
 
       Tenant shall afford Landlord access to the Expansion Space for the
       purpose of completing the Expansion Punch List, which Expansion Punch
       List shall be completed within thirty (30) days after the Landlord's
       receipt of the Expansion Punch List.

            If the Expansion Substantial Completion Date has not occurred by the
       Expansion Construction Completion Date (as it may be extended by the
       terms hereof), Tenant shall have the right to terminate the provisions of
       this Section 14.29 and all of the rights and obligations of Landlord and
       Tenant under this Lease as they relate to the Expansion Space (and only
       the Expansion Space) by giving notice to Landlord, not later than thirty
       (30) days after the Expansion Construction Completion Date (as so
       extended),  of Tenant's desire so to do; and the provisions of this
       Section 14.29 and all of the rights and obligations of Landlord and
       Tenant under this Lease as they relate to the Expansion Space (and only
       the Expansion Space) shall cease and come to an end without further
       liability or obligation on the part of either party seventy-five (75)
       days after the giving of such notice, unless within such seventy-five
       (75) day period, Landlord substantially completes Landlord's Expansion
       Work to the extent required by the provisions of this Section 14.29,
       which substantial completion shall void Tenant's election to terminate;
       and such right of termination shall be Tenant's sole and exclusive remedy
       at law or in equity for Landlord's failure so to complete Landlord's
       Expansion Work within such time.

                 Unless Tenant shall have given Landlord written notice by the
       end of the first ninety (90) days after the Expansion Commencement Date
       of specific respects in which Landlord has not performed Landlord's
       Expansion Work in compliance with the matters set forth in the Expansion
       Space Plan and the final approved Tenant's Expansion Plans, Tenant shall
       have no claim that Landlord has failed to perform any of Landlord's
       Expansion Work. Landlord hereby agrees to perform Landlord's Expansion
       Work (i) in compliance with the requirements of the Americans with
       Disabilities Act of 1990, as amended to the extent applicable) (ii) in
       compliance with all applicable laws, rules, ordinances and codes in
       effect on the Expansion Substantial Completion Date and (iii) in a good
       and workmanlike manner.  Unless Landlord shall lease the Second Expansion
       Space to Workgroup, Landlord hereby agrees that it will not substantially
       alter the present physical layout of the Expansion Space.  In the event
       of any such alteration, Landlord shall, at its sole cost,  restore same
       to its condition prior to such alteration prior to performing Landlord's
       Expansion Work and the costs of such restoration shall not be charged
       against the Expansion Allowance.

                                      -61-
<PAGE>
 
                 If a delay shall occur in the Expansion Substantial Completion
       Date as the result of:

                 (i) any written request by Tenant that Landlord delay in the
       commencement or completion of Landlord's Expansion Work for any reason;
       or

                 (ii) any failure by Tenant to timely deliver the Expansion
       Space Plan beyond July 31, 1996 or any change by Tenant in the Expansion
       Space Plan or Tenant's failure to timely approve Proposed Expansion Plans
       or Expansion Cost Statements (except such changes as are required and
       necessary due to the fact that the Proposed Expansion Plans are not
       submitted to Tenant substantially in accordance with the Expansion Space
       Plan) submitted to Tenant for approval by Landlord; or

                 (iii) any other act or omission of Tenant or its officers,
       partners, agents, servants or contractors; or

                 (iv) any reasonably necessary displacement of any of Landlord's
       Expansion Work from its place in Landlord's construction schedule
       resulting from any of the causes for delay referred to in clauses (i),
       (ii) or (iii) of this paragraph and the fitting of such Work back into
       the schedule;

            then, in any such event, Tenant shall, from time to time and within
       ten (10) days after demand therefor, pay to Landlord for each day the
       Expansion Substantial Completion Date is delayed by reason of the delays
       referred to in clauses (i), (ii), (iii) and (iv) above, an amount equal
       to one day of Basic Rent (pro-rated on a daily basis) applicable to the
       Expansion Space for each such day of delay.  Landlord shall provide
       Tenant with written notice of any circumstances which will result in a
       Tenant's Delay, which notice shall be given at the time of occurrence of
       such circumstance.

            If a delay in the Expansion Substantial Completion Date, or if any
       substantial portion of such delay, is the result of Force Majeure, and
       such delay would not have occurred but for a delay described in (i),
       (ii), (iii) or (iv above, such delay shall be deemed added to the delay
       described in that paragraph.

                 The delays referred to above are herein referred to
       collectively and individually as "Tenant's Delay".

            The Expansion Construction Completion Date shall automatically be
       extended for the period of any delays caused by (i) Tenant's Delay or
       (ii)  Force Majeure (provided that in no event shall Force Majeure alone
       extend the Expansion Construction Completion Date beyond August 31, 1997)
       or (iii) subject to the limitations of 

                                      -62-
<PAGE>
 
       Section 14.29(a), any delay in NEMRB vacating the Expansion Space beyond
       October 31, 1996 but in no event beyond August 31, 1997 in the case of
       NEMRB not vacating.

          (c) If the provisions of this Section 14.29 shall not be terminated
       pursuant to Section 14.29(a) hereof and provided that Landlord shall give
       Tenant a Workgroup Notice indicating that Workgroup will be leasing the
       Second Expansion Space then, Tenant shall lease the First Expansion Space
       from Landlord pursuant to this Section 14.29(c) effective as of the First
       Expansion Commencement Date (as hereafter defined) on the First Expansion
       Commencement Date, the entire First Expansion Space shall be added to and
       included within the "Premises" for all purposes under the Lease without
       the requirement of any further attention on the part of either Landlord
       or Tenant and in such case, effective as of the First Expansion
       Commencement Date, this Lease shall be deemed amended in the following
       respects (and if requested by Landlord, Tenant shall promptly execute and
       deliver an amendment to this Lease reflecting the matters herein set
       forth):

          (i) The Premises and the Premises Rentable Area shall be deemed
       amended to include the entire First Expansion Space within the Premises
       and the Premises and the Premises Rentable Area shall be increased by the
       6,055 rentable square feet included in the First Expansion Space to be
       and consist of a total of 36,238 rentable square feet for all purposes
       under this Lease;

          (ii) Basic Rent per annum shall be increased by an annual amount (the
       "First Expansion Rent") equal to the Per Square Foot Rent Rate (as said
       term is  defined in Section 14.29(b) hereof) from time to time applicable
       multiplied by the number of rentable square feet contained in the First
       Expansion Space;

          (iii) the Escalation Factor shall be deemed increased to be 91.78%
       for all purposes and, accordingly, Tenant's monthly and annual payments
       on account of the Escalation Charges shall be increased to reflect the
       increase in the Premises by virtue of the addition of the First Expansion
       Space;

          (iv) The increases in Basic Rent and Escalation Charges as determined
       pursuant to subparagraphs (i) through (iii) above shall become effective
       on the First Expansion Commencement Date.

                 As used herein, the term "First Expansion Commencement Date"
       shall be the last to occur of (i) January 31, 1997 (the "First Expansion
       Construction Completion Date"), or (ii) the day following the date on
       which the First Expansion Space is "ready for occupancy" as hereafter
       provided. Notwithstanding the foregoing, if Tenant's 

                                      -63-
<PAGE>
 
       personnel shall occupy all or any part of the First Expansion Space for
       the conduct of its business prior to the First Expansion Commencement
       Date, such date shall for all purposes of this Lease be the First
       Expansion Commencement Date. The Tenant shall, upon demand of the
       Landlord, execute a certificate confirming the First Expansion
       Commencement Date as it is determined in accordance with the provisions
       of this paragraph.

               On or before July 31, 1996, Tenant shall deliver to Landlord a
       Space Plan together with certain written specifications (hereafter the
       "First Expansion Space Plan") depicting installations and improvements
       necessary to prepare the First Expansion Space for Tenant's occupancy.
       Upon receipt of the First Expansion Space Plan from Tenant, Landlord
       shall promptly cause its architects and engineers to prepare final
       working drawings and specifications reflecting the work and improvement
       shown on the First Expansion Space Plan (the "Proposed First Expansion
       Plans").  Upon completion of such Proposed First Expansion Plans,
       Landlord shall submit same to Tenant for review and approval together
       with a statement from Landlord (the "First Expansion Cost Statement")
       with respect to whether or not the costs of all work, materials, permit
       fees, architectural fees and engineering fees (the "Cost of First
       Expansion Work") necessary to prepare such Proposed First Expansion Plans
       and to complete the improvements shown thereon exceed $45,335.88 (the
       "First Expansion Allowance").  Such costs set forth in the First
       Expansion Cost Statement which are in excess of the First Expansion
       Allowance (the "First Expansion OBS Costs") shall be borne by Tenant in
       the manner hereafter specified.  Tenant shall either approve or reject
       such Proposed First Expansion Plans within ten (10) days after receipt
       from Landlord.  Tenant hereby agrees to approve and shall not
       unreasonably withhold or delay its approval of such Proposed First
       Expansion Plans provided that they are substantially in compliance with
       those matters set forth in the First Expansion Space Plan.  Failure of
       Tenant to object to any aspect of such Proposed First Expansion Plans
       within the time and manner provided above shall be deemed an approval of
       such Proposed First Expansion Plans and authorization for Landlord to
       proceed with Landlord's First Expansion Work in accordance therewith.
       Tenant shall have the right to consult with Landlord's architect for
       purposes of review and approval of Proposed First Expansion Plans and
       review of the First Expansion Cost Statement.  Landlord and Tenant shall
       each cooperate with the architect in connection with the preparation,
       review and approval of Proposed First Expansion Plans and the
       finalization of Tenant's First Expansion Plans.

               If Tenant shall reject any aspect of such Proposed First
       Expansion Plans within the time and manner provided 

                                      -64-
<PAGE>
 
       above, Landlord shall promptly make such revisions to the Proposed First
       Expansion Plans as may be necessary so as to bring them into substantial
       compliance with the matters set forth in the First Expansion Space Plan
       and shall provide Tenant with a revised First Expansion Cost Statement
       based on the cost of completing the work shown on the revised Proposed
       First Expansion Plans. Tenant shall approve or reject such revised
       Proposed First Expansion Plans and First Expansion Cost Statement within
       ten (10) days after receipt. Tenant shall not unreasonably withhold or
       delay its approval to such revised Proposed First Expansion Plans
       provided that they substantially comply with the First Expansion Space
       Plan. Failure of Tenant to respond within the time and manner herein
       provided shall be deemed a waiver of such right by Tenant and Tenant
       shall be deemed to have approved such revised Proposed First Expansion
       Plans and First Expansion Cost Statement as submitted by Landlord and to
       have authorized Landlord to proceed with Landlord's First Expansion Work
       in accordance therewith. Upon approval by both Landlord and Tenant, such
       working drawings and specifications shall be deemed to be Tenant's First
       Expansion Plans for all purposes under this Lease. The OBS Costs
       described in such revised and accepted First Expansion Cost Statement
       shall, for all purposes hereunder, be deemed to be "First Expansion OBS
       Costs".

                 To the extent that Tenant shall request any changes or
       modifications to Tenant's First Expansion Plans (and provided that
       Landlord shall approve such changes, which approval will not be
       unreasonably withheld or delayed), Tenant shall pay the additional cost
       of completing Landlord's First Expansion Work resulting from such changes
       to Landlord as additional First Expansion OBS Costs hereunder as follows:
       50% of costs shall be paid at the time of approval of such change and 50%
       shall be paid on the First Expansion Commencement Date and Landlord's
       approval of any such proposed changes shall be accompanied by a Statement
       of First Expansion OBS Costs and Tenant's Delay, if any, which will
       result from such changes.  Similarly, all First Expansion OBS Costs shall
       be paid in the same manner, 50% prior to Landlord commencing work and 50%
       on the First Expansion Commencement Date.  Landlord and Tenant shall, if
       requested by the other, execute a work letter confirming such excess
       costs prior to the time Landlord shall be required to commence work.
       Upon final approval of any such revised Tenant's First Expansion Plans by
       Landlord and Tenant, Landlord shall promptly proceed with such Landlord's
       First Expansion Work.

            The First Expansion Space shall be deemed "ready for occupancy" on
       the first Business Day (the "First Expansion Substantial Completion
       Date") following written notice to Tenant that Landlord's First Expansion
       Work has 

                                      -65-
<PAGE>
 
       been completed except for items of work (and, if applicable, adjustment
       of equipment and fixtures) which can be completed after occupancy has
       been taken without causing substantial interference with Tenant's use of
       the First Expansion Space (i.e., so called "punch-list" items. Landlord's
       notice shall be accompanied by Landlord's Architect's certificate of
       completion (certified to Landlord and Tenant) of Landlord's First
       Expansion Work and, if applicable, a Certificate of Occupancy (as defined
       in Section 4.2(b) for the First Expansion Space. It is agreed and
       understood that a so-called "conditional" or "temporary" Certificate of
       Occupancy or Occupancy Permit shall be deemed to satisfy the C of O
       requirement of the immediately preceding sentence, provided that the only
       condition to issuance of a Final C of O then outstanding pertains solely
       to matters or work which are the responsibility of the Tenant rather than
       the obligation or responsibility of Landlord under this Lease. Tenant
       shall provide Landlord with a final punch list (the "First Expansion
       Punch-list") as to the status of completion of Landlord's First Expansion
       Work within ten (10) days after delivery to Tenant of the aforementioned
       notice that the First Expansion Space is "ready for occupancy." Tenant
       shall afford Landlord access to the First Expansion Space for the purpose
       of completing the First Expansion Punch List, which First Expansion Punch
       List shall be completed within thirty (30) days after the Landlord's
       receipt of the First Expansion Punch List.

            If the First Expansion Substantial Completion Date has not occurred
       by the First Expansion Construction Completion Date (as it may be
       extended by the terms hereof), Tenant shall have the right to terminate
       the provisions of this Section 14.29 and all of the rights and
       obligations of Landlord and Tenant under this Lease as they relate to the
       Expansion Space (and only the Expansion Space) by giving notice to
       Landlord, not later than thirty (30) days after the First Expansion
       Construction Completion Date (as so extended),  of Tenant's desire so to
       do; and the provisions of this Section 14.29 and all of the rights and
       obligations of Landlord and Tenant under this Lease as they relate to the
       Expansion Space (and only the Expansion Space) shall cease and come to an
       end without further liability or obligation on the part of either party
       seventy-five (75) days after the giving of such notice, unless within
       such seventy-five (75) day period, Landlord substantially completes
       Landlord's First Expansion Work to the extent required by the provisions
       of this Section 14.29, which substantial completion shall void Tenant's
       election to terminate; and such right of termination shall be Tenant's
       sole and exclusive remedy at law or in equity for Landlord's failure so
       to complete Landlord's First Expansion Work within such time.

                                      -66-
<PAGE>
 
                 Unless Tenant shall have given Landlord written notice by the
       end of the first ninety (90) days after the First Expansion Commencement
       Date of specific respects in which Landlord has not performed Landlord's
       First Expansion Work in compliance with the matters set forth in the
       First Expansion Space Plan and the final approved Tenant's First
       Expansion Plans, Tenant shall have no claim that Landlord has failed to
       perform any of Landlord's First Expansion Work. Landlord hereby agrees to
       perform Landlord's First Expansion Work (i) in compliance with the
       requirements of the Americans with Disabilities Act of 1990, as amended
       to the extent applicable) (ii) in compliance with all applicable laws,
       rules, ordinances and codes in effect on the First Expansion Substantial
       Completion Date and (iii) in a good and workmanlike manner.  Unless
       Landlord shall lease the Second Expansion Space to Workgroup, Landlord
       hereby agrees that it will not substantially alter the present physical
       layout of the Expansion Space between the date of this Lease and the
       First Expansion Commencement Date.  In the event of any such alteration,
       Landlord shall restore same to its condition prior to such alteration.

                 If a delay shall occur in the First Expansion Substantial
       Completion Date as the result of:

                 (i) any written request by Tenant that Landlord delay in the
       commencement or completion of Landlord's First Expansion Work for any
       reason; or

                 (ii) any failure by Tenant to timely deliver the First
       Expansion Space Plan beyond July 31, 1996 or any change by Tenant in the
       First Expansion Space Plan or Tenant's failure to timely approve Proposed
       First Expansion Plans or First Expansion Cost Statements (except such
       changes as are required and necessary due to the fact that the Proposed
       First Expansion Plans are not submitted to Tenant substantially in
       accordance with the First Expansion Space Plan) submitted to Tenant for
       approval by Landlord; or

                 (iii) any other act or omission of Tenant or its officers,
       partners, agents, servants or contractors; or

                 (iv) any reasonably necessary displacement of any of Landlord's
       First Expansion Work from its place in Landlord's construction schedule
       resulting from any of the causes for delay referred to in clauses (i),
       (ii) or (iii) of this paragraph and the fitting of such Work back into
       the schedule;

            then, in any such event, Tenant shall, from time to time and within
       ten (10) days after demand therefor, pay to Landlord for each day the
       First Expansion Substantial 

                                      -67-
<PAGE>
 
       Completion Date is delayed by reason of the delays referred to in clauses
       (i), (ii), (iii) and (iv) above, an amount equal to one day of Basic Rent
       (pro-rated on a daily basis) applicable to the First Expansion Space for
       each such day of delay. Landlord shall provide Tenant with written notice
       of any circumstances which will result in a Tenant's Delay, which notice
       shall be given at the time of occurrence of such circumstance.

            If a delay in the First Expansion Substantial Completion Date, or if
       any substantial portion of such delay, is the result of Force Majeure,
       and such delay would not have occurred but for a delay described in (i),
       (ii), (iii) or (iv) above, such delay shall be deemed added to the delay
       described in that paragraph.

                 The delays referred to above are herein referred to
       collectively and individually as "Tenant's Delay".

            The First Expansion Construction Completion Date shall automatically
       be extended for the period of any delays caused by (i) Tenant's Delay or
       (ii)  Force Majeure (provided that in no event shall Force Majeure alone
       extend the First Expansion Construction Completion Date beyond August 31,
       1997) or (iii) subject to the limitations of Section 14.29(a), any delay
           -                                                                   
       in NEMRB vacating the First Expansion Space beyond October 31, 1996, but
       in no event beyond August 31, 1997 in the case of a delay in NEMRB
       vacating.

          (d) If the provisions of this Section 14.29 shall not be terminated
       pursuant to Section 14.29(a) hereof and provided that Tenant shall have
       leased the First Expansion Space as and when required by the provisions
       of Section 14.29(c) hereof then, Tenant shall lease the Second Expansion
       Space from Landlord pursuant to this Section 14.29(d) and effective as of
       the Second Expansion Commencement Date (as hereafter defined) the entire
       Second Expansion Space shall be added to and included within the
       "Premises" for all purposes under the Lease without the requirement of
       any further attention on the part of either Landlord or Tenant and in
       such case, effective as of the Second Expansion Commencement Date, this
       Lease shall be deemed amended in the following respects (and if requested
       by Landlord, Tenant shall promptly execute and deliver an amendment to
       this Lease reflecting the matters herein set forth):

          (i) The Premises and the Premises Rentable Area shall be deemed
       amended to include the entire Second Expansion Space within the Premises
       and the Premises and the Premises Rentable Area shall be increased by
       3,244 rentable square feet included in the Second Expansion Space to be
       and consist of a total of 39,482 rentable square feet for all purposes
       under this Lease;

                                      -68-
<PAGE>
 
          (ii) Basic Rent per annum shall be increased by an annual amount (the
       "Second Expansion Rent") equal to the Per Square Foot Rent Rate (as said
       term is defined in Section 14.29(b) hereof) from time to time applicable
       multiplied by the number of rentable square feet contained in the Second
       Expansion Space;

          (iii) the Escalation Factor shall be deemed increased to be 100%  for
       all purposes and, accordingly, Tenant's monthly and annual payments on
       account of the Escalation Charges shall be increased to reflect the
       increase in the Premises by virtue of the addition of the Second
       Expansion Space;

          (iv) The increases in Basic Rent and Escalation Charges as determined
       pursuant to subparagraphs (i) through (iii) above shall become effective
       on the Second Expansion Commencement Date.

                 As used herein, the term "Second Expansion Commencement Date"
       shall be the last to occur of (i) January 31, 1998 (the "Second Expansion
       Construction Completion Date"), or (ii) the day following the date on
       which the Second Expansion Space is "ready for occupancy" as hereafter
       provided.  Notwithstanding the foregoing to the contrary, in the event
       that Workgroup shall remain in occupancy of the Second Expansion Space
       beyond October 31, 1997, Landlord, at its sole cost and expense, shall
       promptly commence summary process proceedings to cause the removal or
       eviction of Workgroup from the Expansion Space (and shall thereafter
       diligently pursue such action to completion) upon expiration of the term
       of the Workgroup Lease if Workgroup does not then vacate the Second
       Expansion Space.  Notwithstanding anything contained in this Section
       14.29 to the contrary, in the event that Workgroup shall not vacate the
       Second Expansion Space on or before January 31, 1998, Tenant may, at its
       option, but written notice to Landlord on or before February 5, 1998
       terminate the provisions of this Section 14.29(d) (the "Workgroup
       Termination Right") and all of Landlord and Tenant's rights and
       obligations under this Lease as they pertain to the Second Expansion
       Space (and only as they pertain to the Second Expansion Space), which
       termination shall be effective as of the date of such notice.  Failure of
       Tenant to give Landlord such termination notice within the time and
       manner herein specified shall be deemed a waiver of Tenant's Workgroup
       Termination Right.  Upon Workgroup vacating the Second Expansion Space,
       Landlord shall commence Landlord's Expansion Work (as hereafter defined)
       in the Second Expansion Space.  Notwithstanding the foregoing, if
       Tenant's personnel shall occupy all or any part of the Second Expansion
       Space for the conduct of its business prior to the Second Expansion
       Commencement Date, such 

                                      -69-
<PAGE>
 
       date shall for all purposes of this Lease be the Second Expansion
       Commencement Date. The Tenant shall, upon demand of the Landlord, execute
       a certificate confirming the Second Expansion Commencement Date as it is
       determined in accordance with the provisions of this Section 14.29(d)

               On or before July 31, 1997, Tenant shall deliver to Landlord a
       Space Plan together with certain written specifications (hereafter the
       "Second Expansion Space Plan") depicting installations and improvements
       necessary to prepare the Second Expansion Space for Tenant's occupancy.
       Upon receipt of the Second Expansion Space Plan from Tenant, Landlord
       shall promptly cause its architects and engineers to prepare final
       working drawings and specifications reflecting the work and improvement
       shown on the Second Expansion Space Plan (the "Proposed Second Expansion
       Plans").  Upon completion of such Proposed Second Expansion Plans,
       Landlord shall submit same to Tenant for review and approval together
       with a statement from Landlord (the "Second Expansion Cost Statement")
       with respect to whether or not the costs of all work, materials, permit
       fees, architectural fees and engineering fees (the "Cost of Second
       Expansion Work") necessary to prepare such Proposed Second Expansion
       Plans and to complete the improvements shown thereon exceed $23,293.00
       (the "Second Expansion Allowance").  Such costs set forth in the Second
       Expansion Cost Statement which are in excess of the Second Expansion
       Allowance (the "Second Expansion OBS Costs") shall be borne by Tenant in
       the manner hereafter specified.  Tenant shall either approve or reject
       such Proposed Second Expansion Plans within ten (10) days after receipt
       from Landlord.  Tenant hereby agrees to approve and shall not
       unreasonably withhold or delay its approval of such Proposed Second
       Expansion Plans provided that they are substantially in compliance with
       those matters set forth in the Second Expansion Space Plan.  Failure of
       Tenant to object to any aspect of such Proposed Second Expansion Plans
       within the time and manner provided above shall be deemed an approval of
       such Proposed Second Expansion Plans and authorization for Landlord to
       proceed with Landlord's Second Expansion Work in accordance therewith.
       Tenant shall have the right to consult with Landlord's architect for
       purposes of review and approval of Proposed Second Expansion Plans and
       review of the Second Expansion Cost Statement.  Landlord and Tenant shall
       each cooperate with the architect in connection with the preparation,
       review and approval of Proposed Second Expansion Plans and the
       finalization of Tenant's Second Expansion Plans.

               If Tenant shall reject any aspect of such Proposed Second
       Expansion Plans within the time and manner provided above, Landlord shall
       promptly make such revisions to the 

                                      -70-
<PAGE>
 
       Proposed Second Expansion Plans as may be necessary so as to bring them
       into substantial compliance with the matters set forth in the Second
       Expansion Space Plan and shall provide Tenant with a revised Second
       Expansion Cost Statement based on the cost of completing the work shown
       on the revised Proposed Second Expansion Plans. Tenant shall approve or
       reject such revised Proposed Second Expansion Plans and Second Expansion
       Cost Statement within ten (10) business days after receipt. Tenant shall
       not unreasonably withhold or delay its approval to such revised Proposed
       Second Expansion Plans provided that they substantially comply with the
       Second Expansion Space Plan. Failure of Tenant to respond within the time
       and manner herein provided shall be deemed a waiver of such right by
       Tenant and Tenant shall be deemed to have approved such revised Proposed
       Second Expansion Plans and Second Expansion Cost Statement as submitted
       by Landlord and to have authorized Landlord to proceed with Landlord's
       Second Expansion Work in accordance therewith. Upon approval by both
       Landlord and Tenant, such working drawings and specifications shall be
       deemed to be Tenant's Second Expansion Plans for all purposes under this
       Lease. The OBS Costs described in such revised and accepted Second
       Expansion Cost Statement shall, for all purposes hereunder, be deemed to
       be "Second Expansion OBS Costs".

                 To the extent that Tenant shall request any changes or
       modifications to Tenant's Second Expansion Plans (and provided that
       Landlord shall approve such changes, which approval will not be
       unreasonably withheld or delayed), Tenant shall pay the additional cost
       of completing Landlord's Second Expansion Work resulting from such
       changes to Landlord as additional Second Expansion OBS Costs hereunder as
       follows:  50% of costs shall be paid at the time of approval of such
       change and 50% shall be paid on the Second Expansion Commencement Date
       and Landlord's approval of any such proposed changes shall be accompanied
       by a Statement of Second Expansion OBS Costs and Tenant's Delay, if any,
       which will result from such changes.  Similarly, all Second Expansion OBS
       Costs shall be paid in the same manner, 50% prior to Landlord commencing
       work and 50% on the Second Expansion Commencement Date.  Landlord and
       Tenant shall, if requested by the other, execute a work letter confirming
       such excess costs prior to the time Landlord shall be required to
       commence work.  Upon final approval of any such revised Tenant's Second
       Expansion Plans by Landlord and Tenant, Landlord shall promptly proceed
       with such Landlord's Second Expansion Work.

            The Second Expansion Space shall be deemed "ready for occupancy" on
       the first Business Day (the "Second Expansion Substantial Completion
       Date") following written notice to Tenant that Landlord's Second
       Expansion Work 

                                      -71-
<PAGE>
 
       has been completed except for items of work (and, if applicable,
       adjustment of equipment and fixtures) which can be completed after
       occupancy has been taken without causing substantial interference with
       Tenant's use of the Second Expansion Space (i.e., so called "punch-list"
       items). Landlord's notice shall be accompanied by Landlord's Architect's
       certificate of completion (certified to Landlord and Tenant) of
       Landlord's Second Expansion Work and, if applicable, a C of O (as defined
       in Section 4.2(b) for the Second Expansion Space. It is agreed and
       understood that a so-called "conditional" or "temporary" Certificate of
       Occupancy or Occupancy Permit shall be deemed to satisfy the C of O
       requirement of the immediately preceding sentence, provided that the only
       condition to issuance of a Final C of O then outstanding pertains solely
       to matters or work which are the responsibility of the Tenant rather than
       the obligation or responsibility of Landlord under this Lease. Tenant
       shall provide Landlord with a final punch list (the "Second Expansion
       Punch-list") as to the status of completion of Landlord's Second
       Expansion Work within ten (10) days after delivery to Tenant of the
       aforementioned notice that the Second Expansion Space is "ready for
       occupancy." Tenant shall afford Landlord access to the Second Expansion
       Space for the purpose of completing the Second Expansion Punch List,
       which Second Expansion Punch List shall be completed within thirty (30)
       days after the Landlord's receipt of the Second Expansion Punch List.
       
           If the Second Expansion Substantial Completion Date has not occurred
       by the Second Expansion Construction Completion Date (as it may be
       extended by the terms hereof), Tenant shall have the right to terminate
       the provisions of this Section 14.29(d) and all of the rights and
       obligations of Landlord and Tenant under this Lease as they relate to the
       Second Expansion Space (and only the Second Expansion Space) by giving
       notice to Landlord, not later than thirty (30) days after the Second
       Expansion Construction Completion Date (as so extended),  of Tenant's
       desire so to do; and the provisions of this Section 14.29(d) and all of
       the rights and obligations of Landlord and Tenant under this Lease as
       they relate to the Second Expansion Space (and only the Second Expansion
       Space) shall cease and come to an end without further liability or
       obligation on the part of either party seventy-five (75) days after the
       giving of such notice, unless within such seventy-five (75) day period,
       Landlord substantially completes Landlord's Second Expansion Work to the
       extent required by the provisions of this Section 14.29, which
       substantial completion shall void Tenant's election to terminate; and
       such right of termination shall be Tenant's sole and exclusive remedy at
       law or in equity for Landlord's failure so to complete Landlord's Second
       Expansion Work within such time.

                                      -72-
<PAGE>
 
                 Unless Tenant shall have given Landlord written notice by the
       end of the first ninety (90) days after the Second Expansion Commencement
       Date of specific respects in which Landlord has not performed Landlord's
       Second Expansion Work in compliance with the matters set forth in the
       Second Expansion Space Plan and the final approved Tenant's Second
       Expansion Plans, Tenant shall have no claim that Landlord has failed to
       perform any of Landlord's Second Expansion Work. Landlord hereby agrees
       to perform Landlord's Second Expansion Work (i) in compliance with the
       requirements of the Americans with Disabilities Act of 1990, as amended
       to the extent applicable) (ii) in compliance with all applicable laws,
       rules, ordinances and codes in effect on the Second Expansion Substantial
       Completion Date and (iii) in a good and workmanlike manner.

                 If a delay shall occur in the Second Expansion Substantial
       Completion Date as the result of:

                 (i) any written request by Tenant that Landlord delay in the
       commencement or completion of Landlord's Second Expansion Work for any
       reason; or

                 (ii) any failure by Tenant to timely deliver the Second
       Expansion Space Plan beyond July 31, 1997 or any change by Tenant in the
       Second Expansion Space Plan or Tenant's failure to timely approve
       Proposed Second Expansion Plans or Second Expansion Cost Statements
       (except such changes as are required and necessary due to the fact that
       the Proposed Second Expansion Plans are not submitted to Tenant
       substantially in accordance with the Second Expansion Space Plan)
       submitted to Tenant for approval by Landlord; or

                 (iii) any other act or omission of Tenant or its officers,
       partners, agents, servants or contractors; or

                 (iv) any reasonably necessary displacement of any of Landlord's
       Second Expansion Work from its place in Landlord's construction schedule
       resulting from any of the causes for delay referred to in clauses (i),
       (ii) or (iii) of this paragraph and the fitting of such Work back into
       the schedule;

            then, in any such event, Tenant shall, from time to time and within
       ten (10) days after demand therefor, pay to Landlord for each day the
       Second Expansion Substantial Completion Date is delayed by reason of the
       delays referred to in clauses (i), (ii), (iii) and (iv) above, an amount
       equal to one day of Basic Rent (pro-rated on a daily basis) applicable to
       the Second Expansion Space for each such day of delay.  Landlord shall
       provide Tenant with written notice of any circumstances which will 

                                      -73-
<PAGE>
 
       result in a Tenant's Delay, which notice shall be given at the time of
       occurrence of such circumstance.

            If a delay in the Second Expansion Substantial Completion Date, or
       if any substantial portion of such delay, is the result of Force Majeure,
       and such delay would not have occurred but for a delay described in (i),
       (ii), (iii) or (iv) above, such delay shall be deemed added to the delay
       described in that paragraph.

                 The delays referred to above are herein referred to
       collectively and individually as "Tenant's Delay".

            The Second Expansion Construction Completion Date shall
       automatically be extended for the period of any delays caused by (i)
       Tenant's Delay or (ii)  Force Majeure (provided that in no event shall
       Force Majeure alone extend the Second Expansion Construction Completion
       Date beyond August 31, 1998 or (iii) any delay in Workgroup vacating the
       Second Expansion Space beyond October 31, 1997, but in no event beyond
       August 31, 1998 in the event of Workgroup's failure to vacate.


       14.30  PERMITTED SIGNAGE.   Subject to the terms and conditions hereafter
              ------------------                                                
       set forth and to all applicable building codes, ordinances, by-laws,
       zoning codes and land use restrictions, Landlord has agreed that Tenant
       may (to the extent permitted by applicable law) erect one sign (the
                                                                      -   
       "Building Sign") on the exterior facade of the Building and one sign (the
                      -                                                         
       "Entry Sign") on the ground at the entrance to the Property in the
       vicinity of the existing street number sign (the Building Sign and the
       Entry Sign are sometimes hereafter collectively the "Exterior Sign").  It
       is hereby expressly agreed and understood that each Exterior Sign shall
       consist only of Tenant's name and logo.  Landlord hereby reserves the
       right to review and approve the content, size, color, manner of
       illumination, manner of attachment to the Building (in the case of the
                                                          -                  
       Building sign) and location of each Exterior Sign, which approval shall
       not be unreasonably withheld or delayed by Landlord but with such
       reasonable additional conditions as Landlord may deem appropriate in its
       reasonable discretion.  Landlord hereby approves those matters set forth
       hereinabove which are specifically expressed, provided and/or described
       in Exhibit H.

       Tenant shall be responsible (at its sole cost and expense) for obtaining
       all necessary governmental permits, approvals and authorizations for the
       approved Exterior Sign.  Copies of all such permits, approvals and
       authorizations shall be delivered to Landlord prior to Tenant performing
       any work.  In addition, Tenant shall, at its sole cost and expense, (i)
       pay for all work and materials, permits, and approvals necessary for the
       erection of the Exterior Signs (ii) continuously throughout the Term of
       this Lease, maintain and repair the Exterior Signs and (iii) upon any
       expiration or earlier termination of the 

                                      -74-
<PAGE>
 
       Term of this Lease, remove the Exterior Signs from the

       Property, repairing any and all damage to the Building and the Property
       resulting from the installation and removal of such Exterior Sign.

          It is expressly agreed and understood that Landlord shall not be
       responsible for any costs or expenses in any way pertaining or related to
       the installation, repair, maintenance or removal of the Exterior Sign.
       The provisions of Article V of the Lease shall be applicable to Tenant's
       installation of the Exterior Sign.  Landlord makes no representation or
       warranty as to whether the Exterior Sign will be permitted by applicable
       laws, ordinances or codes.

      IN WITNESS WHEREOF, Landlord and Tenant have caused this Lease to be duly
executed, under seal, by persons hereunto duly authorized, in multiple copies,
each to be considered an original hereof, as of the date first set forth above.

TENANT:                   LANDLORD:
-------                   ---------

Desktop Data, Inc.            Teachers Realty
                              Corporation


By:                           By:  
   ----------------------        ------------------------ 
                                 Richard J. Usas
Its:                             Its:  Assistant Secretary
    ---------------------     

                                      -75-
<PAGE>
 
                                   EXHIBIT E
                                   ---------

                     (ITEMS INCLUDED IN OPERATING EXPENSES)



          Without limitation, Operating Expenses shall include:

               1. All expenses incurred by Landlord or Landlord's agents which
          shall be directly related to employment of personnel, including
          amounts incurred for wages, salaries and other compensation for
          services, payroll, social security, unemployment and similar taxes,
          workmen's compensation insurance, disability benefits, pensions,
          hospitalization, retirement plans and group insurance, uniforms and
          working clothes and the cleaning thereof, and expenses imposed on
          Landlord or Landlord's agents in connection with the operation,
          repair, maintenance, cleaning, management and protection of the
          Property, and its mechanical systems including, without limitation,
          day and night supervisors, property manager, accountants, bookkeepers,
          janitors, carpenters, engineers, mechanics, electricians and plumbers
          and personnel engaged in supervision of any of the persons mentioned
          above excluding persons higher than Building Manager: provided that,
          if any such employee is also employed on other property of Landlord,
          such compensation shall be suitably allocated on a proportionate basis
          by Landlord among the Property and such other properties based on time
          spent.

               2. The cost of services, materials and supplies furnished or used
          in the operation, repair, maintenance, cleaning, management and
          protection of the Property including, without limitation, fees and
          assessments, if any, imposed upon Landlord, or charged to the
          Property, by any governmental agency or authority or other duly
          authorized private or public entity on account of public safety
          services, transit, housing, police, fire, sanitation or other services
          or purported benefits.

               3. The cost of replacements for tools and other similar equipment
          used in the repair, maintenance, cleaning and protection of the
          Property, provided that, in the case of any such equipment used
          jointly on other property of Landlord, such costs shall be allocated
          by Landlord among the Property and such other properties.

               4. Premiums for insurance against damage or loss to the Building
          from such hazards as shall from time to time be generally required by
          institutional mortgagees in the Boston area for similar properties,
          including, but not by way of limitation, insurance covering loss of
          rent attributable to any such hazards, and public liability insurance.

               5. Where the Property is managed by Landlord or an affiliate of
          Landlord, a sum equal to the amounts customarily charged by management
          firms in the Boston area for similar properties, but in no event more
          than six percent (6%) of gross annual income, whether or not actually
          paid, or where managed by other than Landlord or an affiliate thereof,
          the amounts accrued for management, together with, in either case,
          amounts accrued for legal and other professional fees relating to the
          Property, but excluding such fees and commissions paid in connection
          with services rendered for securing or renewing leases and for matters
          not related to the normal administration and operation of the
          Building.

               6. If, at any time during the Term of this Lease after expiration
          of the First Lease Year, Landlord shall make a capital expenditure,
          the total cost of which is not properly includable in Operating
          Expenses for the Operating Year in which it was made and (i) such
          capital expenditure was made in order to bring the Building into
          compliance with any law, code, ordinance, by-law or statute not in
          effect as of the date of this Lease or (ii) such capital 

                                      -76-
<PAGE>
 
          expenditure was made in order to make the Building more operationally
          efficient or in order to reduce Operating Expenses (regardless of
          whether or not such efficiencies or reductions shall actually result)
          then in any such case, there shall nevertheless be included in
          Operating Expenses for the Operating Year in which it was made and in
          Operating Expenses for each succeeding Operating Year the annual
          charge-off of such expenditure. The annual charge-off shall be
          determined by dividing the original capital expenditure plus an
          interest factor, reasonably determined by Landlord, as being the
          interest rate then being charged for long-term mortgages, by
          institutional lenders on like properties within the locality in which
          the Building is located, by the number of years of useful life of the
          capital expenditure, and the useful life shall be determined
          reasonably by Landlord in accordance with generally accepted
          accounting principles and practices in effect at the time of making
          such expenditure.

               7. Betterment assessments provided the same are apportioned
          equally over the longest period permitted by law.

               8. Amounts paid to independent contractors for services,
          materials and supplies furnished for the operation, repair,
          maintenance, cleaning and protection of the Property.

          The following shall not be included in Operating Expenses:

     The following shall not be included in Operating Expenses:

     (a)  Work & Services.  Leasehold improvements, alterations and decorations
          ---------------                                                      
          or other work done for specific tenants of the Building.

     (b)  Promotional Expenses.  Advertising and promotional expenditures or
          --------------------                                              
          contributions or gifts.

     (c)  Leasing Costs.  Costs incurred in connection with Landlord's
          -------------                                               
          preparation, negotiation and/or enforcement of leases, including court
          costs and attorneys' fees and disbursements in connection with any
          summary proceeding to dispossess any tenant.

     (d)  Financing Costs.  Financing and refinancing costs in respect of any
          ---------------                                                    
          mortgage placed upon the Property, including points and commissions in
          connection therewith.

     (e)  Interest & Penalties.  Interest or penalties for any late payments by
          --------------------                                                 
          Landlord.

     (f)  Brokerage Commissions.  Leasing and brokerage fees and commissions.
          ---------------------                                              

     (g)  Building Additions.  Costs of constructing any additional floors or
          ------------------                                                 
          rentable area to the Building after the original construction.

     (h)  Interest and Amortization.  Interest or amortization on any loan or
          -------------------------                                          
          mortgage with respect to the Land or the Building.

     (i)  Legal & Accounting.  Legal and auditing fees or other professional
          ------------------                                                
          fees, other than those reasonably incurred in connection with the
          maintenance and routine management and operation of the Land and
          Building.

     (j)  Ground Rent.  Rent or other charges payable under any ground or
          -----------                                                    
          underlying lease.

     (k)  Licenses & Permits.  Costs and expenses of governmental licenses and
          ------------------                                                  
          permits, or renewals thereof, unless the same are for governmental
          licenses or permits normal to the operation or maintenance of the Land
          or Building.

                                      -77-
<PAGE>
 
                                   EXHIBIT G

                             RULES AND REGULATIONS


          1. The sidewalks, paved and/or landscaped areas shall not be
obstructed or encumbered by Tenant or used for any purpose other than ingress
and egress to and from the demised premises.

          2. No sign, advertisement, notice or other lettering shall be
exhibited, inscribed, painted or affixed by Tenant on any part of the demised
premises or Building so as to be visible from outside the demised premises
without the prior written consent of Landlord, which will not be unreasonably
withheld or delayed. In the event of the violation of this paragraph, Landlord
may remove same without any liability, and may charge the expense incurred in
such removal to Tenant, as additional rent.

          3. No awnings, curtains, blinds, shades, screens or other projections
shall be attached to or hung in, or used in connection with, any window of the
demised premises or any outside wall of the Building without the prior written
consent of Landlord, which will not be unreasonably withheld or delayed so long
as said upon other portions of the Building. Such awnings, curtains, blinds,
shades, screens or other projections must be of a quality, type, design and
color, and attached in the manner, approved by Landlord. If any portion of the
demised premises which is not used for office purposes shall have windows, such
windows shall be equipped with curtains, blinds or shades approved by Landlord,
and said curtains, blinds or shades shall be kept closed at all times.

          4. The water and wash closets and other plumbing fixtures shall not be
used for any purposes other than those for which they were designed and
constructed, and no sweepings, rubbish, rags, acids, chemicals, process water,
cooling water or like substances shall be deposited therein. Said plumbing
fixtures and the discharge of so-called sanitary waste. All damage resulting
from any misuse of said fixtures and/or plumbing system by Tenant or anyone
claiming under Tenant shall be borne by Tenant.

          5. Tenant must, upon the termination of its tenancy, return to
Landlord all locks, cylinders and keys to the demised premises and any offices
therein

          6. Tenant shall keep any sidewalks and planters in front of the
demised premises reasonably free and clear of litter and refuse, regardless of
the source thereof.

          7. Intentionally Omitted.

          8. Tenant shall not make, or permit to be made, any unseemly or
disturbing odors or noises or disturb or interfere with occupants of the
Building or those having business with them, whether by use of any musical
instrument, radio machine, or in any other way.

          9. Canvassing, soliciting, and peddling in the Building are prohibited
and Tenant shall cooperate to prevent the same.
   
         10. Tenant shall keep the demised premises free at all time of pests,
rodents and other vermin, and Tenant shall keep all trash and rubbish stored in
containers of a type approved by Landlord, such containers to be kept at
locations designated by Landlord. Tenant shall cause such containers to be
emptied whenever necessary to prevent them from overflowing or form producing
any objectionable odors.

          11. Landlord reserves the right to rescind, alter, waive and/or
establish any reasonable rules and regulations of uniform application to all
tenants which, in its judgment, are necessary, desirable or proper for its best
interests and the best interests of the occupants of the Building.

          12. The access roads, driveways, entrances and exits shall not be
obstructed or encumbered by Tenant or used for any purpose other than ingress
and egress.

                                      -78-
<PAGE>
 
                                   EXHIBIT H
                                   ---------

                           TENANT'S APPROVED SIGNAGE
                           -------------------------



     As f the date of this Lease, Tenant has not provided any information
     regarding signage.  Accordingly, any signage proposed by Tenant shall be
     subject to the provisions of Article V and this Section 14.30.

                                      -79-