Exhibit (10)(ii)(D)


                                      LEASE

                                     between

                  TWO TWENTY TWO BERKELEY VENTURE, as LANDLORD


                                       and

                       HOUGHTON MIFFLIN COMPANY, as TENANT


                          Dated as of December 16, 1991



<PAGE>



                             BASIC LEASE INFORMATION


Date:                           December 16, 1991

Tenant:                         Houghton Mifflin Company

Address:                        One Beacon Street
                                Boston, MA 02108

Landlord:                       Two Twenty Two Berkeley Venture

Address:                        c/o Hines Interests Limited Partnership
                                500 Boylston Street, Suite 1800
                                Boston, MA 02116

Location of Leased              Floors three (3) through eleven (11), as
Premises:                       shown on Exhibit A, of the Building located
                                on the Land described in Exhibit A-1

Net Rentable Area:              263,923 square feet

Term Commencement Date:         March 1, 1992

Scheduled Completion Date:      March 1, 1993

Estimated Outside               December l, 1993
Completion Date:

Scheduled Rent
Commencement Date:              March 1, 1994

Term Expiration Date:           The thirteenth (13th) anniversary of the
                                Rent Commencement Date

Options to Extend Term:         Either (A)  One (1) two year option
                                       or
                                       (B) One (1) five year option,
                                           and one (1) subsequent option
                                           for, as determined by
                                           Landlord pursuant to Section
                                           9.01, either five years or
                                           ten years

Base Rent                       Years 1 - 10: $12.27 per square foot per
                                year of Net Rentable Area leased
                                Years 11 - 15: $15.55 per square foot per year
                                of Net Rentable Area leased


                                       -2-


<PAGE>




Tenant's Proportionate          The ratio, expressed as a percentage, of the Net
Share:                          Rentable Area of the Leased Premises to the
                                greater of (i) ninety-five percent (95%) of the
                                total Net Rentable Area of the Office Section,
                                or (ii) the Total Leased Net Rentable Area. As
                                of the date of this Lease, based on 95% of the
                                total Net Rentable Area of the Office Section,
                                the Tenant's Proportionate Share is 58.67%



































                                       -3-






<PAGE>





                                      INDEX
                                      -----


SECTION                                                                   PAGE
NUMBER                                                                   NUMBER
-------                                                                  ------


         Basic Lease Information.........................................   2

         Schedule of Exhibits............................................   9

         ARTICLE l. LEASE

1.01     Lease...........................................................  10

         ARTICLE 2. TERM; USE; RENT

2.01     Term............................................................  10

2.02     Use.............................................................  12

2.03     Rent............................................................  12

2.04     Operating Cost..................................................  12

2.05     Impositions.....................................................  19

2.06     Computation of Operating Cost and
         Impositions.....................................................  20

2.07     Adjustment for Variation Between Estimated
         and Actual Operating Cost and Impositions.......................  23

2.08     Notice of Adjustments...........................................  23

2.09     Operating Cost for 1994.........................................  23

         ARTICLE 3.   LANDLORD'S COVENANTS

3.01     Basic Services..................................................  24

3.02     Extra Services..................................................  27

3.03     Graphics and Signage............................................  28

3.04     Repair Obligation...............................................  29

3.05     Peaceful Employment.............................................  30

3.06     Restricted Uses.................................................  30



                                       -4-


<PAGE>



SECTION                                                                   PAGE
NUMBER                                                                   NUMBER
------                                                                   ------


         ARTICLE 4. TENANT'S COVENANTS

4.01     Construction of Tenant Improvements............................   30

4.02     Taxes on Personal Property.....................................   30

4.03     Repairs by Tenant..............................................   31

4.04     Waste..........................................................   31

4.05     Assignment or Sublease.........................................   31

4.06     Alterations and Surrender......................................   36

4.07     Compliance with Laws and Insurance Standards...................   39

4.08     Entry for Repairs and Leasing..................................   39

4.09     No Nuisance....................................................   40

4.10     Subordination..................................................   40

4.11     Estoppel Certificate...........................................   41

4.12     Tenant's Remedies..............................................   41

4.13     Rules and Regulations..........................................   42

4.14     Personal Property at Tenant's Risk.............................   42

4.15     Payment of Landlord's Expenses.................................   42

4.16     Window Coverings...............................................   43

         ARTICLE 5. CASUALTY and EMINENT DOMAIN

5.01     Casualty Insurance.............................................   43

5.02     Liability Insurance............................................   44

5.03     Tenant's Insurance.............................................   44

5.04     Indemnity and Exoneration......................................   46

5.05     Waiver of Subrogation Rights...................................   47

                                       -5-




<PAGE>



SECTION                                                                   PAGE
NUMBER                                                                   NUMBER
------                                                                   ------

5.06     Condemnation and Loss or Damage................................   47

5.07     Damage Due to Fire and Casualty................................   49

         ARTICLE 6. DEFAULT

6.01     Events of Default..............................................   52

6.02     Remedies upon Default..........................................   54

6.03     Damages upon Termination.......................................   54

6.04     Computation of Rent for Purposes of Default....................   56

6.05     Rights of Landlord in Bankruptcy...............................   56

6.06     Interest on Late Payments.......................................  56

         ARTICLE 7. APPRAISAL

7.01     Appraisal of Fair Market Net Rent..............................   57

         ARTICLE 8. MISCELLANEOUS

8.01     Holding Over...................................................   59

8.02     Amendments and Modifications...................................   60

8.03     Transfers by Landlord..........................................   60

8.04     Severability...................................................   60

8.05     Notices........................................................   60

8.06     No Joint Venture...............................................   61

8.07     Successors and Assigns.........................................   61

8.08     Applicable Law.................................................   61

8.09     Time of the Essence............................................   61

8.10     Submission Not an Option ......................................   61

8.11     Brokerage......................................................   61

8.12     Waiver of Jury Trial...........................................   62



                                       -6-

<PAGE>




SECTION                                                                   PAGE
NUMBER                                                                   NUMBER
------                                                                   ------

8.13     All Agreements Contained......................................    62

8.14     Cumulative Remedies...........................................    62

8.15     Failure to Enforce.............................................   62

8.16     Notice of Lease; Other Notices and Agreements.................    63

8.17     Moving Expense Reimbursement..................................    63

8.18     Release of Existing Lease Obligations.........................    63

8.19     Hiring Practices..............................................    64

         ARTICLE 9. OPTIONS TO EXTEND THE TERM

9.01     Grant and Exercise of Options to Extend.......................    64

9.02     Election to Reduce the Leased Premises........................    65

9.03     Rent During Extended Term.....................................    66

9.04     Lease Continues in Effect.....................................    67

         ARTICLE 10. OPTIONS TO EXPAND THE LEASED PREMISES

10.01    Grant of Initial Option to Expand.............................    67

10.02    Grant of Options to Expand....................................    67

10.03    Exercise of Options to Expand.................................    69

10.04    Rent for Expansion Space......................................    70

10.05    Condition of Expansion Space..................................    71

10.06    Expansion Space Part of Leased Premises.......................    71

         ARTICLE 11. FIRST RIGHT TO LEASE

11.01    Exercise of First Right to Lease..............................    72

         ARTICLE 12. ADDITIONAL OPTIONS

12.01    Parking.......................................................    74


                                       -7-


<PAGE>



SECTION                                                                   PAGE
NUMBER                                                                   NUMBER
------                                                                   ------

12.02    Storage Area..................................................    75

12.03    Antenna or Satellite Dish.....................................    76

12.04    Security......................................................    76

12.05    Exhibits......................................................    77

         ARTICLE 13. DEFINITIONS

13.01    Definitions...................................................    77

Signatures



<PAGE>



                              SCHEDULE OF EXHIBITS


Exhibit A               Leased Premises

Exhibit A-1             Description of Land

Exhibit A-2             Description of 500 Boylston Parcel

Exhibit B               Work Letter

Exhibit C               Storage Area

Exhibit D               Building Rules and Regulations

Exhibit E               Net Rentable Area of Floors in the Building

Exhibit F               Berkeley Entrance Graphic

Exhibit G               Paving Graphic

Exhibit H               Location of Tenant Directory Board

Exhibit I               Janitorial Service to Leased Premises

Exhibit J               Impositions on the Building as of the date of the
                        Lease








                                       -9-


<PAGE>




         THIS LEASE is entered into as of the date hereof  between  Landlord and
Tenant.


                                    ARTICLE 1

                                      LEASE
                                      -----


1.01. Lease. Landlord leases to Tenant and Tenant leases from Landlord the
Leased Premises, and as appurtenant to the Leased premises, the right to use in
common with others entitled thereto, the Common Areas, the Project Common Areas,
the Loading Docks and the Parking Section, all upon the terms, covenants and
conditions set forth herein.


                                    ARTICLE 2

                                 TERM; USE; RENT
                                 ---------------


2.01. Term. Except as otherwise provided herein, this Lease shall commence on
the Term Commencement Date, and shall continue in full force for the Term.
Except as otherwise provided herein, Landlord's obligations under this Lease
shall commence upon the date hereof. Tenant's obligations under this Lease shall
commence upon the Completion Date (except as expressly otherwise provided herein
with respect to obligations arising earlier), unless Tenant shall have taken
occupancy of all or any portion of the Leased Premises for the conduct of its
business on an earlier date, in which case such obligations shall commence on
the date of such occupancy, but only with respect to any floor or portion
thereof so occupied by Tenant. Notwithstanding the foregoing, Tenant's
obligation to pay Gross Rent shall commence upon the Rent Commencement Date,
unless subsequent to the Scheduled Rent Commencement Date but prior to the Rent
Commencement Date Tenant shall have taken occupancy of all or any portion of the
Leased Premises for the conduct of its business in which case Tenant's
obligation to pay Gross Rent shall commence upon such occupancy, but any such
obligation shall commence only with respect to any floor or portion thereof so
occupied by Tenant, Landlord agrees to use reasonable efforts to Substantially
Complete the Leased Premises by the Scheduled Completion Date, failing which,
Landlord shall continue to use reasonable efforts to Substantially Complete the
Leased Premises unless and until this Lease shall have been terminated pursuant
to this Section 2.01 (which agreement shall hereinafter be referred to as
"Landlord's Delivery Covenant"). If the Leased Premises are not Substantially
Complete by the




                                      -10-



<PAGE>



Scheduled Completion Date for any reason, Landlord shall not be liable for any
claims, damages or liabilities by reason thereof, but the Rent Commencement Date
shall be delayed by two (2) days for each day of such delay in Substantial
Completion, unless and to the extent such delay was caused by Force Majeure or
any Tenant's Delay (in which case the Rent Commencement Date shall not be so
delayed). Landlord shall use reasonable efforts to give Tenant notice of the
occurrence of any event which may cause a delay in the Completion Date beyond
the Scheduled Completion Date, and the estimated length of any such delay. In
any event, if landlord fails to give Tenant written notice within three (3)
Business Days of the occurrence of any such event, then any Tenant Delay caused
thereby shall not be deemed to have commenced until the date such notice is
given. Landlord shall also provide Tenant with thirty (30) days prior notice of
the date when Landlord reasonably expects to achieve Substantial Completion,
based upon the progress of the work. Tenant will commence occupancy of the
Leased Premises after the Completion Date, with occupancy of no less than
seventy five percent (75%) of the Leased Premises (including the executive
offices of Tenant) by the first anniversary of the Completion Date. If Landlord
has not commenced construction of the Initial Tenant Improvements by the date
which is one hundred and twenty (120) days prior to the Outside Completion Date,
then for so long as such failure to commence construction shall continue, Tenant
may give Landlord notice of its intent to terminate this Lease if such
construction is not commenced within the next thirty (30) days following such
notice, and, if construction is not commenced within such period, then Tenant
may terminate this Lease by notice to Landlord given within thirty (30) days
following the expiration of the initial thirty (30) day period. So long as
Landlord is not in default of Landlord's Delivery Covenant, this right of
termination shall be Tenant's sole remedy in the event construction is not
commenced as aforesaid. If the Leased Premises are not Substantially Complete by
the Outside Completion Date, then for so long as the Leased Premises are not
Substantially Complete, Tenant may give Landlord notice of its intent to
terminate this Lease if Substantial Completion does not occur within the next
thirty (30) days following such notice, and, if Substantial Completion does not
occur within such period, then Tenant may terminate this Lease by notice to
Landlord given within thirty (30) days following the expiration of the initial
thirty (30) day period, Tenant shall have the continuing right to terminate this
Lease at any time before Substantial Completion occurs in the same manner as
provided in the immediately preceding sentence. So long as Landlord is not in
default of Landlord's Delivery Covenant, this right of termination shall be
Tenant's sole remedy in the event Substantial Completion does not occur. If
Tenant gives Landlord notice that Tenant desires to terminate this Lease under
the terms

                                      -11-


<PAGE>



of the previous three sentences of this Section 2.1, then, as a condition to
such termination Tenant shall reimburse Landlord for all previously
uncompensated Tenant Extra Costs; such termination shall not be deemed effective
unless such costs and expenses are paid in full. In the event Tenant provides
Landlord with such notice of termination and this Lease is terminated in
accordance with the provisions of this paragraph, Tenant shall not be liable to
Landlord for any Tenant Extra Costs incurred by Landlord after the date of such
notices. If Substantial Completion does not occur within eighteen (18) months
after the Estimated Outside Completion Date (as extended by any period of delay
to the extent resulting from Landlord's failure to fulfill Landlord's Delivery
Covenant), then Landlord shall have the right to terminate this Lease by notice
to Tenant.

2.02. Use. Tenant shall use the Leased Premises solely for the Permitted Use and
for no other use or purpose, except as permitted by Landlord pursuant to
Landlord's written consent (which consent Landlord may withhold in its absolute
and sole discretion).

2.03. Rent. All obligations of Tenant to make payments to Landlord under this
Lease shall constitute Rent. Tenant shall pay the Rent at the times and in the
manner hereinafter set forth. All Rent shall be paid in lawful money of the
United States, Gross Rent shall be paid commencing on the Rent Commencement Date
and continuing thereafter in twelve (12) equal monthly installments (subject,
however, to an adjustment of the portion thereof representing Tenant's
Proportionate Share of the Estimated Operating Cost and Tenant's Proportionate
Share of the Estimated Impositions in accordance with Section 2.08) on the first
day of each calendar month during each year of the Term and any extensions
thereof, in advance without demand, and all Rent shall be paid without any
reduction, abatement counterclaim or set-off (except as expressly set forth in
Sections 3.01(b), 5.06(b) and 5.07(e)), at the address for Landlord specified on
the Basic Lease Information sheet or at such other address as may be designated
in a notice by Landlord from time to time. If the Rent Commencement Date occurs
on other than the first day of a month, then Gross Rent provided for such
partial month shall be equitably prorated on such date of commencement. If the
Term terminates on other than the last day of a calendar month, then Gross Rent
provided for such partial month shall be equitably prorated on such date of
termination.

2.04. Operating Cost.

      (a) Operating Cost shall mean all expenses and costs of every kind and
          nature incurred by Landlord in its reasonable business judgment which
          Landlord shall pay or


                                      -12-


<PAGE>




          become obligated to pay because of or in connection with the
          management, maintenance, preservation or operation of the Building
          (determined in accordance with generally accepted accounting
          principles, consistently applied) including, but not limited to the
          following:

          (1) Expenses of the operation, maintenance and security of the
              Building, including compensation in the form of wages, salaries,
              and other compensation and benefits (including payroll taxes,
              federal, state and local unemployment taxes and social security
              taxes), insurance, welfare and retirement benefits, and related
              expenses and benefits of all on-site employees (not exceeding the
              level of property manager) and off-site employees (but only to the
              extent such employees are involved directly in the operation,
              maintenance, management and preservation of the Building, and with
              respect to off-site employees above the level of the property
              manager directly responsible for the Building, only so long as
              Hines Interests Limited Partnership or an affiliate thereof is
              managing the Building; it being agreed that the manner in which
              Landlord allocates the expenses for such off-site employees and
              categories to which such expenses are allocated will not change
              from the manner utilized by Landlord as of the date of this Lease
              and Landlord agrees to certify that such manner and categories
              have not changed (the "Allocable Share Certification") in
              connection with the delivery by Landlord to Tenant of the
              statement of the Operating Cost and Impositions pursuant to
              Section 2.06) but excluding employees and other personnel to the
              extent they are engaged in the initial development and
              construction of the Building;

          (2) The Building's allocable share of the cost incurred by Landlord in
              Greater Boston for Landlord's office and management office
              operation for the Building (provided, however, that if such office
              is located outside the Project, such allocable share shall not
              exceed the allocable share of the cost which would have been
              incurred had the office been located within the Project);

          (3) All tools, supplies materials and equipment used in the operation
              and maintenance of the Building (the "Building Equipment"),
              including rental fees for the same, if such items are not
              purchased and


                                      -13-

<PAGE>




              amortized, or, if Landlord in its reasonable business judgement
              determines that it is ultimately less costly to purchase than to
              rent, then the cost of such Building Equipment, as amortized by
              Landlord in accordance with requirements governing the
              amortization of such Building Equipment under the Internal Revenue
              Code, together with reasonable financing charges (the
              reasonableness of such financing charges to be determined with
              reference to the rates then being offered by institutional lenders
              for such financing);

          (4) Utilities, including water and power, sewer, gas, heating,
              lighting, air conditioning and ventilating the entire Building
              (provided, however, that should any tenant in the Building,
              including Tenant, have special needs or uses requiring the use of
              any such utility beyond the ordinary for a typical tenant in a
              first-class office building like the Building, as determined by
              Landlord in its reasonable judgment (which, in the case of
              electrical usage, is established pursuant to Section 3.01(a)(v)
              and (vi)), Landlord shall monitor such additional usage by the
              installation of meters or by other reasonable means, exclude the
              cost of such additional usage from the Operating Cost and bill the
              tenant directly therefor);

          (5) All maintenance, janitorial and service agreements or costs for
              the Building, including, without limitation, alarm service,
              landscaping, window cleaning, escalator and elevator maintenance,
              rubbish and snow removal, pest control, equipment maintenance or
              servicing or maintenance or cleaning for sidewalks, Building
              exterior, roof and service areas (provided, however, that the
              additional cost for any such services beyond the ordinary for
              providing such services to typical tenants in a first-class office
              building like the Building or which are made necessary by the
              special needs or uses of any party, including Tenant, as
              determined by Landlord in its reasonable judgment, shall not be
              included in the Operating Cost but shall be billed directly to
              such party);

          (6) A management cost recovery in connection with the operation of the
              Building; Tenant's share to be three percent (3%) of all Gross
              Rent, excluding such cost recovery;



                                      -14-


<PAGE>



          (7) Legal and accounting services for the Building, including the
              costs of audits by certified public accountants; excluding,
              however, the cost of dispute resolution auditing of the Operating
              Cost or Impositions pursuant to leases with tenants in the
              Building, costs incurred as a result of the negligence or willful
              misconduct of Landlord or Landlord Responsible Parties, costs
              incurred in proceedings against any specific tenant, and costs
              incurred in connection with the financing, refinancing, leasing,
              development and/or construction of, the Building;

          (8) All insurance premiums and costs applicable to the Building and
              Landlord's personal property used in connection therewith,
              including but not limited to, the premiums and cost of fire,
              casualty and liability coverage and rental abatement or business
              interruption insurance;

          (9) Repairs (including, where necessary, replacements which do not
              constitute capital improvements) together with reasonable
              financing charges until the full cost of such repairs is repaid to
              Landlord by tenants in the Building (the reasonableness of such
              financing charges to be determined with reference to the rates
              then being offered by institutional lenders for such financing)
              and general maintenance (except for repairs the cost of which is
              paid for by, or would have been paid for by, the proceeds of
              insurance which Landlord is required to carry pursuant to Section
              5.01 of this Lease or which are paid for directly by Tenant or
              other third parties, and except for alterations to the extent
              attributable to tenants of the Building);

         (10) Capital improvements made to the Building, including replacements
              as amortized by Landlord in accordance with requirements governing
              the amortization of such capital improvements under the Internal
              Revenue Code, together with reasonable financing charges (the
              reasonableness of such financing charges to be determined with
              reference to the rates then being offered by institutional lenders
              for such financing) subsequent to the Completion Date which (i)
              are designed to and will improve the operating efficiency of the
              Building,

                                      -15-


<PAGE>


              or (ii) may be required by governmental authorities pursuant to
              applicable laws, ordinances or regulations subsequent to the
              approval of the Initial Tenant Improvement Plans (other than those
              which are required for the exclusive benefit of an individual
              tenant or tenants and not relating to the general use or operation
              of the Building); provided, however, that the amount of such
              amortization and financing charges for items in (i) above shall
              not exceed in any year the amount of costs reasonably determined
              by Landlord to have been saved in such year by the expenditure
              either through direct reduction or minimization of increases which
              would have otherwise occurred, and provided further that with
              respect to (ii) above, Landlord shall take reasonable steps to
              comply with such governmental requirements in the most economical
              manner.

      (b) Notwithstanding any other provision herein to the contrary, in the
          event that the Building is not fully occupied during any year of the
          Term, an adjustment shall be made in computing those items
          constituting components of Operating Cost which vary depending on the
          level of occupancy of the Building for such year so that Operating
          Cost shall be extrapolated and computed as though the Building had
          been fully occupied during such year; provided, however, that in no
          event shall Landlord collect in total, from Tenant and all other
          tenants of the Building, an amount greater than one hundred percent
          (100%) of the actual Operating Cost during any year of the Term.

      (c) Notwithstanding the foregoing, Operating Cost shall not include any
          costs and expenses excluded expressly by the provisions of subsection
          (a) above or any costs and expenses relating to:

          (1) the management, maintenance, preservation or operation of (i) the
              Parking Section, (ii) the Commercial Section, to the extent
              constituting leasable space for tenants of the Commercial Section,
              and (iii) the Common Areas to the extent reasonably allocable to
              the Parking Section or the Commercial Section;

                                      -16-


<PAGE>



          (2) any special needs or uses of tenants with respect to storage areas
              resulting in extraordinary costs or expenses in connection with
              maintaining, repairing and operating such storage areas;

          (3) leasing commissions or tenants inducements associated with leasing
              activities;

          (4) costs or improvements to any tenant's leased premises or otherwise
              exclusively for the benefit of an individual tenant;

          (5) principal, interest, late charges or other payments on loans
              (except as provided in (a)(3), (a)(9) or (a)(10) above), ground
              rent, rent paid for the right to locate Project Common Areas or
              Loading Docks outside of the Building, or payments on equity
              obligations;

          (6) costs of repairing, replacing or otherwise correcting defects in
              the design or construction of the Project, or design or
              construction defects in any leasehold improvements in rentable
              areas of the Building;

          (7) leasing commissions, attorneys' fees, costs and disbursements and
              other expenses, any of which are incurred in connection with
              negotiations or disputes with tenants or prospective tenants,
              except with respect to disputes with other tenants the resolution
              of which is reasonably likely to result in a material benefit to
              the tenants of the Project (other than costs incurred in
              connection with the lease termination and eviction of any tenant);

          (8) depreciation and amortization of the Project or equipment, except
              as provided in (a)(3) and (a)(10) above;

          (9) expenses in connection with services of a type which Tenant does
              not receive under this Lease but which are provided to another
              tenant;

         (10) fines, penalties or indemnification obligations incurred due to
              violations by Landlord or Landlord Responsible Parties of any
              governmental rule or authority, or any agreement made in
              connection therewith with a governmental entity, and any costs



                                      -17-


<PAGE>



              of remedying such violations or defending the prosecution thereof
              (except for the costs of remedying such violations to the extent
              such costs are permitted Operating Costs pursuant to Section
              2.04(a)(10));

         (11) all amounts paid to principals, subsidiaries, affiliates or other
              parties related to Landlord for services for the Project in excess
              of the amount payable for comparable services provided by a party
              who is not a principal, subsidiary, affiliate or otherwise related
              party;

         (12) costs and expenses to the extent related to the ownership (as
              distinguished from operation and maintenance, including the
              charges contemplated by (a)(2) above) of the Project;

         (13) any particular items and services for which Tenant otherwise
              reimburses Landlord by direct payment over and above Base Rent and
              Tenant's Proportionate Share of Operating Cost;

         (14) advertising, marketing, promotional and like expenditures;

         (15) costs of refinancing the Project;

         (16) interest or penalties resulting from delinquent payments by
              Landlord, provided such delinquent payments are not caused by
              Tenant;

         (17) repairs or other work occasioned by fire, windstorm or other
              casualty to the extent covered by insurance required to be carried
              by Landlord hereunder, or by the exercise of the right of eminent
              domain, or voluntary conveyance in lieu thereof, to the extent
              reimbursed by condemnation proceeds;

         (18) Landlord's costs of electricity and other services to the extent
              they are separately chargeable to tenants as an additional charge
              or rental over and above the regular installments of rent payable
              under the lease with such tenant;






                                      -18-


<PAGE>



         (19) costs incurred by Landlord which are considered capital
              improvements and replacements under generally accepted accounting
              principles ("GAAP") including contributions to replacement or
              contingency reserves created by Landlord, except as provided in
              (a)(3) or (a)(10) above;

         (20) any compensation paid to clerks, attendants, or other persons in
              commercial concessions operated by Landlord; and

         (21) costs for the purchase of sculpture, paintings, or other objects
              of art, and any royalties payable in connection therewith; and

         (22) the cost of any curative action required, or any repair,
              replacement or alteration made, by Landlord (or by a third party,
              the cost of which is imposed upon Landlord) to remedy a condition
              or damage caused by or resulting from the negligence or willful
              misconduct of Landlord or Landlord Responsible Parties, and,
              except to the extent such costs are permitted Operating Costs
              pursuant to Section 2.04(a)(10), the costs of complying with
              governmental or insurance requirements to the extent caused by a
              condition existing as of the date the Initial Tenant Improvement
              Plans are approved unless and to the extent caused by Tenant.

2.05. Impositions. Impositions shall mean all real estate or personal property
taxes, possessory interest taxes, so-called "linkage payments" made by Landlord
with respect to the Building pursuant to that certain Development Impact Project
Agreement dated as of June 28, 1985, as amended by that certain First Amendment
to Development Impact Project Agreement dated as of May 11, 1988 and as the same
may be further amended (provided that if any further amendment increases the
amount to be paid by Landlord, such increase shall not constitute an
Imposition), or similar charges, business or license taxes or fees, service
payments in lieu of such taxes or fees, annual or periodic license or use fees,
excises, assessments, levies, fees or charges, general and special, ordinary and
extraordinary, unforeseen as well as foreseen, of any kind (including fees
"in-lieu" of any such tax or assessment) payable over the longest permitted
period (provided no extra costs are incurred as a result thereof), which are
assessed, levied, charged, confirmed or imposed by any public authority upon the
Land, the Building, its operations or the Rent (or any portion or component
thereof) including in the year paid, all reasonable fees and costs incurred by
Landlord in seeking to



                                      -19-


<PAGE>



obtain an abatement or reduction of, or a limit on any increase, in any taxes,
regardless of whether any abatement, reduction or limitation is obtained, but
excluding (i) inheritance or estate taxes imposed upon or assessed against the
Building, or any part thereof or interest therein, (ii) taxes computed upon the
basis of the net income derived from the Building by Landlord or the owner of
any interest therein, (iii) that portion of the items enumerated in this Section
which is allocable to the Commercial Section or the Parking Section of the
Building and (iv) any involuntary payments which Landlord may agree to make with
respect to the Building after the date hereof. Attached hereto as Exhibit J is
an itemization of the Impositions for 1991 and the respective amounts thereof,
on an annualized basis, which currently relate to the Building. Landlord
represents that it is not aware of any other Impositions affecting the Building
as of the date hereof; however, Landlord and Tenant acknowledge that said
itemization of Impositions may change during the Term hereof. Upon the written
request of Tenant, Landlord will either (x) institute such proceedings as it
may, in its reasonable business judgment, consider appropriate to seek an
abatement of the Impositions, or (y) permit Tenant to institute such proceedings
as it may, in its reasonable business judgment, consider appropriate to seek an
abatement of the Impositions, provided that if Landlord reasonably believes that
there is not a reasonable probability of success (without regard to the impact
of such proceedings upon any building other than the Building), Landlord may
refuse to permit Tenant to institute any such proceedings.

2.06. Computation of Operating Cost and Impositions.

      (a) Landlord shall, within a reasonable period of time following each
          calendar year, give Tenant a statement of the Operating Cost and
          Impositions during such calendar year (prepared by a certified public
          accountant), which shall be accompanied by a computation of Tenant's
          Proportionate Share of such Operating Cost and Impositions and an
          Allocable Share Certification. Landlord agrees to use reasonable
          efforts to provide Tenant, within one hundred and twenty (120) days
          after each calendar year, with either such statement or a written
          explanation of why such statement is not available, but Landlord's
          failure to provide Tenant with either such statement or such written
          explanation within said period shall not release either party from the
          obligation to make the adjustment provided for in Section 2.07.
          Notwithstanding the foregoing, Landlord shall have no right to collect
          an adjustment under Section 2.07 for a given calendar year should
          Landlord


                                      -20-


<PAGE>



          fail to deliver such statement within three hundred and sixty (360)
          days after such calendar year. Tenant shall have the right, for one
          hundred and eighty (180) days following the presentation of such
          statement by Landlord, to examine and audit Landlord's books and
          records with respect to the Operating Cost and/or Impositions for such
          calendar year (it being agreed that Tenant shall not have the right,
          beyond that otherwise provided herein, to audit the books and records
          which establish the basis for the Allocable Share Certification). If
          the results of such audit indicate that Tenant has overpaid its share
          of Operating Cost or Impositions for such calendar year, Tenant shall
          give notice to Landlord of the results of the audit within said one
          hundred and eighty (180) day period (the "Overpayment Notice"), which
          notice shall be accompanied by a copy of the audit together with a
          statement in reasonable detail of the reasonable cost of such audit,
          and thereupon Landlord may elect to either (i) pay to Tenant the
          amount of such overpayment, plus, if Tenant has overpaid its share of
          Operating Cost or Impositions for such calendar year by more than
          three percent (3%), the reasonable cost of such audit, within thirty
          (30) days of the Overpayment Notice or (ii) submit the issue to the
          dispute resolution procedure set forth in subsection 2.06(b) by notice
          given to Tenant within thirty (30) days of the Overpayment Notice (the
          "Dispute Resolution Notice"). In the event that Landlord delivers its
          statement of Operating Cost and Impositions for the calendar year more
          than one hundred and twenty (120) days after the end of the calendar
          year and in the event that Tenant has overpaid its share of Operating
          Cost or Impositions for such calendar year, then if Tenant complies
          with the provisions of the immediately preceding sentence and if
          Tenant is not otherwise in default hereunder beyond any applicable
          grace period, Landlord shall pay Tenant, together with the amount of
          Tenant's overpayment interest to Tenant on the amount of such
          overpayment calculated from the first day of the calendar year
          following such calendar year to the date of repayment to Tenant at the
          then prime rate of the Bank of Boston, or any successor institution
          thereto.

      (b) Landlord and Tenant shall each within thirty (30) days after Landlord
          gives the Dispute Resolution Notice to Tenant appoint a person to act
          as the expert on its behalf and notify the other of such appointment.
          Each expert shall have at least ten (10) years experience in the
          operation of first-class commercial office


                                      -21-


<PAGE>



          buildings. If either party shall fail to so appoint an expert within
          said thirty (30) day period, the expert appointed by the other shall
          determine the issue. In the event that the two experts are appointed
          within said thirty (30) day period, the experts so chosen shall meet
          within ten (10) business days after the second expert is appointed to
          determine Tenant's Proportionate Share of Operating Cost or
          Impositions, as the case may be.

          If the two experts are unable to agree within ten (10) business days
          after such first meeting, they shall appoint a third expert, who shall
          be a competent and impartial person with qualifications similar to
          those required of the first two experts. In the event the two experts
          are unable to agree upon such appointment within five (5) business
          days after the expiration of said ten (10) day period, then either
          party, on behalf of both, may request the appointment of such
          qualified person by an officer of the American Arbitration Association
          in Boston. The expert appointed by each party shall state in writing
          his or her determination of Tenant's Proportionate Share of Operating
          Cost or Impositions, as the case may be, supported by the reasons
          therefor, with counterpart copies to each party. The experts shall
          arrange for a simultaneous exchange of such proposed determinations.
          The role of the third expert shall be to select which of the two
          proposed determinations most closely approximates his own
          determination, and the third expert shall have no right to propose a
          middle ground or any modification of either of the two proposed
          determinations. The determination chosen by the third expert shall
          constitute the decision of the experts and shall be final and binding
          upon the parties. This provision for determination shall be
          specifically enforceable to the extent such remedies are available
          under applicable law, and either party shall have the right to enter
          judgment thereon, unless otherwise provided by applicable law.
          Landlord and Tenant shall each pay for the fees and disbursements of
          any expert appointed by it and shall share equally in the fees and
          expenses of any third expert.

          In the event of a failure, refusal or inability of any expert to act,
          his or her successor shall be appointed by him or her, but in the case
          of the third expert, his or her successor shall be appointed in the
          same manner as provided for appointment of the third expert.





                                      -22-


<PAGE>



2.07. Adjustment for Variation Between Estimated and Actual Operating Cost and
Impositions. If the Operating Cost and/or the Impositions for any calendar year
exceed, respectively, the Estimated Operating Cost and/or the Estimated
Impositions, Tenant shall pay to Landlord Tenant's Proportionate Share of such
excess within thirty (30) days after presentation of Landlord's statement
pursuant to Section 2.06. If the Operating Cost and/or Impositions for any
calendar year are less than, respectively, the Estimated Operating Cost and/or
the Estimated Impositions, then Landlord shall pay to Tenant Tenant's
Proportionate Share of such difference with the presentation of Landlord's
statement pursuant to Section 2.06. Should the Rent Commencement Date occur or
the Term of this Lease terminate at any time other than on the first day of a
calendar year, Tenant's Proportionate Share of the Operating Cost and/or the
Impositions shall be prorated for the exact number of calendar days occurring in
the partial year in question, and in the case of any termination, the provisions
of this Section 2.07 shall survive such termination.

2.08. Notice of Adjustments. Commencing with the calendar year during which the
Rent Commencement Date occurs and prior to each subsequent calendar year during
the Term, and otherwise from time to time as Landlord deems appropriate,
Landlord shall give Tenant notice of Tenant's Proportionate Share of the
Estimated Operating Cost and Tenant's Proportionate Share of the Estimated
Impositions set forth in reasonable detail, Tenant shall thereafter pay
Landlord, in accordance with the provisions of Section 2.03, Tenant's
Proportionate Share of such Estimated Operating Cost and such Estimated
Impositions. For any calendar year, or portion thereof, for which Landlord does
not provide Tenant with the notice referred to in this Section 2.08, Tenant
shall pay Tenant's Proportionate Share of the Estimated Operating Cost and
Tenant's Proportionate Share of the Estimated Impositions at the rate for the
previous calendar year, subject, however, to the annual adjustment described in
Section 2.06 and Section 2.07.

2.09. Operating Cost for 1994. Notwithstanding anything in this Lease to the
contrary, the Operating Cost for the calendar year 1994 shall in no event exceed
the amount set forth in this Section 2.09. As of the date hereof, the Tenant's
Proportionate Share of Operating Cost which will be a part of the Gross Rent is
$6.71 per square foot of Net Rentable Area. Of this $6.71, electricity charges,
water and sewer charges, insurance premiums, and management cost recovery of
three percent (3%) thereon is $2.63 per square foot of Net Rentable Area. The
balance of the Tenant's Proportionate Share of Operating Cost is $4.08 per
square foot of Net Rentable Area. In the 1994 calendar year, Tenant's
Proportionate Share of Operating Cost with respect to all Operating Cost, other
than the costs incurred by Landlord as part



                                      -23-


<PAGE>



of Operating Cost constituting electricity charges, water and sewer charges,
insurance premiums and management cost recovery of three percent (3%) thereon
shall not exceed the sum of (a) $4.08 per square foot of Net Rentable Area and
(b) the product of (i) the percentage increase in the United States Department
of Labor, Bureau of Labor Statistics Consumer Price Index (All Urban Consumers,
All Items, 1982-1984 equals 100) between Calendar Year 1991 and Calendar Year
1994 and (ii) $4.08 per square foot of Net Rentable Area. If such Index is
discontinued or revised, the average rate of inflation shall be determined by
reference to the index designated as the successor or substitute index by the
government of the United States.


                                    ARTICLE 3

                              LANDLORD'S COVENANTS
                               -------------------

3.01. Basic Services. Landlord or its affiliates shall operate the Building to a
standard of quality consistent with that of first-class office buildings in
Boston, Massachusetts and shall:

      (a) Furnish Tenant during the hours contemplated hereunder during Tenant's
          occupancy of the Leased Premises:

          (i) Water used by the building standard cooling, drinking and
              sanitation systems, domestic hot and cold water and water for
              maintenance and janitorial services, such water to be available at
              all times.

         (ii) During Business Hours, central heat, ventilation and air
              conditioning which, subject to applicable laws, ordinances, rules
              and regulations (but not any voluntary standards) shall be
              sufficient during the season in question to meet the following
              temperature requirements under load conditions which do not exceed
              occupancy of one (1) person per one hundred (100) square feet of
              usable area and power consumption for lighting and electrical
              equipment at a rate of four (4) watts per square foot of usable
              area, with no humidity control and assuming the use of appropriate
              blinds on all windows to shade the Leased Premises: (1) a minimum
              temperature of 72 degrees Fahrenheit inside, plus or minus 2
              degrees, with a minimum






                                      -24-


<PAGE>



              temperature outside of 0 degrees Fahrenheit, and (2) a maximum
              temperature of 76 degrees Fahrenheit inside, plus or minus 2
              degrees, with a maximum temperature outside of 91 degrees
              Fahrenheit (dry bulb) or 75 degrees Fahrenheit (wet bulb).

        (iii) Maintenance, repairs, structural and exterior maintenance
              (including glass and glazing for the exterior of the Building and
              for the Winter Garden), painting and electric lighting service for
              the Project Common Areas and the Common Areas in the manner and to
              the extent customarily provided by landlords in first-class office
              buildings in Boston, such maintenance, repairs and service to be
              provided at such times as Landlord may reasonably determine.

         (iv) Janitorial service to the Leased Premises in accordance with
              Exhibit I, after Business Hours on Business Days (except as
              otherwise set forth in Exhibit I).

          (v) Electricity for typewriters, voice writers, calculating machines,
              low consumption duplicating machines, low consumption electronic
              data processing equipment, and other machines of similar low
              electrical consumption (it being agreed that Tenant's total
              consumption for such items shall not exceed one (1) watt per
              square foot of Net Rentable Area per month at one hundred and
              twenty (120) volts). The electricity shall be provided from a
              central bus duct which shall have the capacity to deliver two (2)
              watts per square foot of two hundred and seventy-seven (277) volt
              single phase electricity and two (2) watts per square foot of one
              hundred and twenty (120) volt single phase electricity.

         (vi) Initial lamps, bulbs, starters and ballasts for building standard
              fixtures used within the Leased Premises, replacement bulbs
              (including the replacement of such bulbs) for building standard
              fixtures used within the Leased Premises for one year following
              the Tenant's initial occupancy of the Leased Premises for the
              purpose of conducting its business, and electricity for lighting
              such fixtures.




                                      -25-


<PAGE>



        (vii) Security for the Building consistent with the operation of a
              first-class office building in downtown Boston, which as of the
              date hereof includes security personnel during Business Hours and
              a card access system during non-Business Hours. Notwithstanding
              the foregoing, Landlord shall have the right to alter specific
              aspects of said security, so long as the level of security
              provided at all times during the Term is comparable or exceeds the
              level provided as of the date of this Lease.

       (viii) Public elevator service serving the floors on which the Leased
              Premises are situated, including (x) during Business Hours, three
              (3) elevators in the low rise bank of elevators, five (5)
              elevators in the high rise bank of elevators, and a freight
              elevator and (y) after Business Hours, elevator service as
              reasonably determined by Landlord consistent with the standards of
              a first class office building, but in no event less than one (1)
              elevator in the low rise bank of elevators and one (1) elevator in
              the high rise bank of elevators during such hours.

         (ix) Access to, and the right in common with other tenants of the
              Building to use, the Loading Docks, subject to Landlord's
              reasonable rules and regulations.

      (b) Landlord shall not be liable for injuries to persons or damage to
          property, nor shall Landlord be deemed to have evicted Tenant, nor
          shall there be any abatement of Rent (except as expressly set forth in
          this Section 3.01(b)), nor shall Tenant be relieved from performance
          of any covenant on its part to be performed hereunder by reason of (i)
          deficiency in the provision of Basic Services (except to the extent
          caused by the negligence or willful misconduct of Landlord or Landlord
          Responsible Parties), (ii) breakdown of equipment or machinery
          utilized in supplying services or (iii) curtailment or cessation of
          services due to causes or circumstances beyond the reasonable control
          of Landlord or Landlord Responsible Parties. Landlord shall use
          reasonable diligence to make or cause to be made such repairs as may
          be required to machinery or equipment within the Building or the
          Project Common Areas to provide restoration of services and, where the
          cessation or interruption of service has occurred due to


                                      -26-


<PAGE>



          circumstances or conditions beyond the Building boundaries, to cause
          the same to be restored, by diligent application or request to the
          provider thereof. Landlord also agrees to use reasonable efforts to
          avoid unnecessary inconvenience to Tenant by reason thereof and
          agrees, where reasonable, not to perform such work during Business
          Hours. In the event Landlord fails to provide or cause to be provided
          any one or more Basic Services, and such failure causes the Leased
          Premises, or a portion thereof, to be rendered untenantable for the
          purpose of conducting Tenant's business operations, and such condition
          shall continue for any three (3) consecutive Business Days after
          Tenant's notice thereof to Landlord or such condition shall occur on
          any five (5) Business Days during any thirty (30) day period after
          Tenant's notice thereof to Landlord, Tenant shall have the right to
          abate the portion of Gross Rent which corresponds to the portion of
          the Leased Premises rendered untenantable.

3.02. Extra Services. Landlord shall provide to Tenant at Tenant's sole cost and
expense at standard Building charges in effect from time to time (which, in the
case of services described in subparagraphs (a), (b) and (e) below shall be
reimbursed by Tenant at Landlord's actual cost, and which in all cases shall be
reasonably consistent with amounts charged by Landlords of other first class
office buildings in the City of Boston providing such extra services) and
subject to the limitations hereinafter set forth, the following:

      (a) Heating, ventilation, or air conditioning provided by Landlord to
          Tenant (i) during hours other than Business Hours, (ii) on days other
          than Business Days, said heating, ventilation or air conditioning to
          be furnished solely upon the prior written request of Tenant given
          with such advance notice as Landlord may reasonably require (but not
          exceeding two (2) Business Days);

      (b) Chilled and/or condenser water required by reason of any electrical,
          data processing or other equipment or facilities or services required
          to support the same, in excess of that which would be required for
          Building Standard Improvements;

      (c) Repair and maintenance which is the obligation of Tenant hereunder
          which Tenant requests Landlord to perform and Landlord agrees to
          perform;




                                      -27-


<PAGE>



      (d) Additional cleaning and janitorial services beyond those specified in
          Exhibit I;

      (e) Additional electricity above the standards specified in Sections
          3.01(a)(v) and (vi), as determined by reference to a separate meter or
          meters measuring Tenant's electrical consumption, which shall be
          included in the plans to be prepared in accordance with the Work
          Letter and installed as part of the Initial Tenant Improvements;

      (f) maintenance and replacement of initial lamps, bulbs, starters and
          ballasts (except as provided in Section 3.01(a)(vi));

      (g) Except as otherwise contemplated by this Section 3.02, any Basic
          Service in amounts which exceed the amounts required to be provided
          under Section 3.01(a), but only if Landlord elects to provide such
          additional or excess service.

3.03. Graphics and Signage. Landlord shall provide, at Landlord's expense,
Tenant or Building identification on the main entrance of the Building in the
locations shown as 2 and 3 on, and otherwise in accordance with, Exhibit F and
in the granite paving on Boylston Street in accordance with Exhibit G and
Landlord shall provide, at Tenant's expense, Tenant identification on the main
entrance of the Building in the location shown as 1 on, and otherwise in
accordance with, Exhibit F and in the granite paving on Berkeley Street and St.
James Avenue in accordance with Exhibit G. The referenced graphics shall remain
a part of the Building as long as an Event of Default has not occurred and is
not continuing under Section 6.01 of this Lease, and Tenant and/or any Tenant
Affiliates are in occupancy of at least seventy-five percent (75%) of the Net
Rentable Area included in the Leased Premises on the Term Commencement Date.
Landlord shall provide on the Building directory board in the main lobby of the
Building a space for Tenant's name and space for up to one (1) name per floor
occupied by Tenant in the Building. Landlord shall provide space on the Building
directory board in the main lobby of the Building to any subtenant or assignee
of Tenant permitted under the provisions of Section 4.05 hereof, equivalent to
the space to which such subtenant or assignee would have been reasonably
entitled if the subtenant or assignee had entered into a lease with Landlord
directly for the same premises demised pursuant to the sublease or assignment
with Tenant. So long as Tenant and/or any Tenant Affiliates are in occupancy of
at least seventy-five percent (75%) Of the Net Rentable Area included in the
Leased Premises on the Term Commencement Date, Landlord shall provide Tenant, at
Tenant's


                                      -28-


<PAGE>



option and at Tenant's expense, a directory board solely for tenant in the main
lobby of the Building, of the same quality and character as the main directory
in the location shown on Exhibit H. So long as Tenant and/or any Tenant
Affiliates are in occupancy of at lease fifty percent (50%) of the Net Rentable
Area included in the Office Section of the Building, Landlord agrees that (a)
except for retail tenants having frontage on Berkeley street, no other tenant or
other occupant of the Building or project shall have a sign or other
identification on the exterior of the Berkeley Street side of the Building
(including the sidewalk in front thereof), and (b) no other tenant or other
occupant of the Building or Project will be permitted to have a sign or other
identification in the first floor front lobby of the Building unless Tenant
shall be offered the option to maintain a sign of equal or greater quality,
character and prominence. All signs, notices and graphics of every kind or
character, visible in or from the Common Areas or the exterior of the Leased
Premises shall be subject to Landlord's prior approval, which Landlord shall
have the right to withhold in its absolute and sole discretion.

3.04. Repair Obligation. Subject to the provisions of Article V, Landlord shall
be obligated to maintain, repair and, as necessary, replace, (or to cause to be
maintained, repaired or replaced), consistent with maintaining the Building as a
first class office building, only the following: (i) the structural portions of
the Building, (ii) the exterior walls of the Building (which shall include walls
facing the Winter Garden as if the same were exterior walls), including glass
and glazing, (iii) the roof, (iv) mechanical, electrical, plumbing and life
safety systems located in the Building, whether within the Leased Premises or
otherwise, (v) the Common Areas and the Project Operational Common Areas, and
(vi) any damage caused to the Leased Premises by any act or omission of Landlord
or Landlord Responsible Parties. If, within ten (10) Business Days after notice
from Tenant, Landlord shall fail or refuse to either (a) commence diligently
work of repair which Landlord is required to perform pursuant to clause (vi) of
this Section 3.04, or (b) provide Tenant with an explanation of why such work of
repair has not been commenced, then, so long as such work does not affect the
items referred to in items (i) through (v) of this Section 3.04 and does not
affect other tenant's of the Project, Tenant shall have the right, but not the
obligation, to perform such work and all reasonable costs incurred by Tenant in
performing such work shall be repaid by Landlord within (10) days of Landlord's
receipt of an invoice therefor. If Tenant shall fail or refuse to commence
diligently work of repair which Tenant is required to perform pursuant to
Section 4.03 within ten (10) Business Days after notice from Landlord (except in
cases of emergency, in which event no prior notice shall be


                                      -29-


<PAGE>



required), or Tenant does not thereafter diligently pursue such work of repair
to completion, then Landlord shall have the right, but not the obligation, to
perform such work and all costs incurred by Landlord in performing any such work
for the account of Tenant shall be repaid by Tenant to Landlord upon demand,
together with an amount equal to ten percent (10%) of such costs, to reimburse
Landlord for its administration and managerial effort. Landlord agrees to use
reasonable efforts to avoid unnecessary inconvenience to Tenant by reason of any
work performed pursuant to Landlord's repair obligations contained in this
Section 3.04.

3.05. Peaceful Enjoyment. So long as Tenant pays the Rent and performs all of
Tenant's covenants and agreements contained in this Lease after any required
notice and within any applicable cure periods, Tenant shall peacefully have,
hold and enjoy the Leased Premises.

3.06. Restricted Uses. Landlord agrees that it will not enter into a lease for
space in the Building under which the tenant thereunder is permitted to use the
premises so leased for offices of any agency or bureau of the United States or
any state or political subdivision thereof without the prior written approval of
Tenant, unless Landlord determines in its reasonable business judgment that such
use is consistent with the operation of the Building as a first class office
building in Boston.


                                    ARTICLE 4

                               TENANT'S COVENANTS
                                -----------------

4.01. Construction of Tenant Improvements. All additions to or improvements of
the Leased Premises, including, without limitation, the Initial Tenant
Improvements, shall become the property of Landlord upon termination of this
Lease and shall be surrendered to Landlord upon termination of this Lease by
lapse of time or otherwise, subject to Tenant's rights and obligations of
removal with respect thereto in the same manner as provided in Section 4.06,
unless Tenant has notified Landlord and Landlord has agreed in writing prior to
installation thereof to allow some or all of the Tenant Improvements to remain
the property of Tenant.

4.02. Taxes on Personal Property. In addition to, and wholly apart from its
obligation to pay Tenant's Proportionate Share of Operating Costs and
Impositions, Tenant shall be responsible for and shall pay, prior to
delinquency, any taxes imposed upon, levied with respect to or assessed against
Tenant's Personal



                                      -30-


<PAGE>



Property, or the value of the Tenant Improvements, or any other tax, charge,
levy or fee imposed in substitution therefor. To the extent that any such taxes
are not separately assessed and billed to Tenant, but are reasonably allocable
to Tenant and billed to Landlord, Tenant shall pay the amount thereof as
invoiced to Tenant by Landlord.

4.03. Repairs by Tenant. Except to the extent of Landlord's responsibility
hereunder for such maintenance and repairs, Tenant shall be obligated for
maintenance and repair of the Leased Premises, to keep the same in good order,
repair and condition, reasonable wear and tear and damage by casualty or
condemnation excepted. Tenant's obligation shall include, without limitation,
the obligation to maintain and repair all walls, floors, ceilings, windows,
doors and fixtures (except for windows located on the exterior of the Building
or overlooking the Winter Garden, the structural portions of the Building and
the mechanical, electrical, plumbing and life safety systems located in the
Building, unless the damage thereto is caused by the negligence of Tenant or any
Tenant Responsible Party, in which event such maintenance or repair shall be
performed by Landlord and Tenant shall pay to Landlord the costs of such
maintenance or repair), and to repair all damage caused by Tenant or any Tenant
Responsible Party to the Building, subject however to the provisions of Section
5.05 below. At the request of Tenant, Landlord shall perform the work of
maintenance and repair constituting Tenant's obligation pursuant to this Section
4.03 at Tenant's sole cost and expense and as an extra service to be rendered
pursuant to Section 3.02(c). Any work of repair performed by or for the account
of Tenant by persons other than Landlord shall be performed by contractors
reasonably approved by Landlord and in accordance with the provisions of Section
4.06 below. Nothing herein contained, however, shall be deemed to impose upon
Tenant the obligation for performance of work of maintenance and repair required
to be performed by reason of Landlord's negligence or willful misconduct or
those of any Landlord Responsible Party.

4.04. Waste. Tenant shall not commit waste or allow any waste or damage to occur
in any portion of the Leased Premises.

4.05. Assignment or Sublease.

      (a) In the event Tenant assigns this Lease or sublets the Leased Premises
          or any part thereof to a Tenant Affiliate, then Tenant shall give
          Landlord notice of such assignment or sublease no later than the
          consummation of such assignment or sublease, unless it is not
          reasonably possible to give notice by such time,



                                      -31-


<PAGE>



          in which event Tenant shall give Landlord notice thereof as soon as
          reasonably practicable thereafter, Landlord's approval shall not be
          required, but Tenant shall, at the time of such notice, provide
          Landlord with a copy of all executed documents effecting such
          assignment or sublease.

      (b) Subject to the provisions hereof, Tenant shall have the right to
          assign or sublet the Leased Premises, or any portion thereof, to a
          person or entity other than a Tenant Affiliate on the earlier of: (i)
          the second anniversary of the Term Commencement Date, or (ii) the date
          on which 95% of Net Rentable Area of the Office Section in the
          Building is initially leased. In the event Tenant intends to assign
          this Lease or sublet the Leased Premises or any part thereof to a
          person or entity other than a Tenant Affiliate, then Tenant shall give
          Landlord notice of such intent.

          (1) If Tenant and/or any Tenant Affiliates are in occupancy of at
              least seventy-five (75%) of the Net Rentable Area included in the
              Leased Premises on the Term Commencement Date, any such assignment
              of this Lease or subletting of the Leased Premises shall be
              subject to Landlord's right to consent or withhold consent thereto
              as hereinafter provided, and Tenant shall provide Landlord with
              (i) the name of the proposed assignee or sublessee, (ii) such
              information as to the financial responsibility and standing of the
              assignee or subtenant as Landlord shall reasonably require, (iii)
              such of the relevant terms and provisions upon which the proposed
              assignment or subletting is to be made as Landlord shall
              reasonably require, (iv) any additional information or documents
              reasonably requested by Landlord. Landlord shall have a period of
              ten (10) days following the receipt of any additional information
              (or twenty (20) days from the date of Tenant's original notice, if
              Landlord does not request additional information) within which to
              notify Tenant whether or not Landlord consents to the proposed
              assignment or sublease. Landlord's right to withhold consent to
              any such proposed assignment or sublease shall be limited to one
              or more of the following reasons: (x) the use of the Leased
              Premises by the proposed assignee or sublessee would not
              constitute a Permitted Use, (y) the character and business
              reputation of the proposed assignee or sublessee is



                                      -32-


<PAGE>



              inconsistent with the character of the Building as a first-class
              office building, or (z) the proposed assignee or sublessee is not
              of sound financial condition as determined by Landlord in the
              reasonable exercise of its business judgement. If Landlord should
              fail to notify Tenant whether or not Landlord consents to the
              proposed assignment or sublease within said period, Landlord shall
              be deemed to have consented thereto. In no event shall a failure
              by Landlord to approve or disapprove a proposed subtenant or
              assignee cause a termination of this Lease.

          (2) If Tenant and/or any Tenant Affiliates are in occupancy of less
              than seventy-five (75%) of the Net Rentable Area included in the
              Leased Premises on the Term Commencement Date, Tenant's notice to
              Landlord of its intention to sublet or assign space shall be
              accompanied by (i) a summary of the proposed business terms
              (including, without limitation, financial terms) on which Tenant
              intends to assign this Lease or sublet said space, (ii) the
              location of the sublet space, if a proposed sublease, and (iii)
              any additional information or documents as Landlord may reasonably
              require. Landlord shall have a period of ten (10) days following
              the receipt of any additional information (or twenty (20) days
              from the date of the Tenant's original notice, if Landlord does
              not request additional information) within which to notify Tenant
              of Landlord's election either (i) to terminate that portion of the
              Leased Premises so affected by Tenant's desire to sublet or the
              entire Leased Premises if Tenant's desire is to assign this Lease,
              or (ii) permit Tenant to market said space. If Landlord should
              fail to notify Tenant of its election within said period, Landlord
              shall be deemed to have allowed Tenant to market said space. If
              Landlord cancels this Lease as to a portion of the Leased Premises
              as provided above, Landlord and Tenant shall enter into a
              modification of the Lease so as to equitably reflect the effects
              of such cancellation of the space. If Landlord cancels this Lease
              as to the entire Leased Premises as provided above, Landlord and
              Tenant shall execute such documents as are reasonably necessary to
              memorialize such cancellation. If Landlord shall allow Tenant to
              market said space, when Tenant has




                                      -33-


<PAGE>



              located such assignee or sublessee, the Tenant shall notify
              Landlord in accordance with the provisions of subparagraph (1)
              above and the other provisions thereof shall apply.

          (3) Notwithstanding anything in this Lease to the contrary, Tenant
              shall not assign this Lease, nor sublet the Leased Premises or any
              portion thereof, to any person or entity who is then a tenant or
              subtenant in the Project or who has executed a lease or sublease
              to occupy space in the Project, unless at the time Tenant requests
              Landlord's consent to assign this Lease or sublet space (i)
              ninety-five (95%) or more of the total rentable area of the
              Project is subject to leases which have not been terminated by
              either Landlord or the tenants thereunder the terms of which
              extend at least three (3) months beyond the commencement date of
              the proposed assignment or sublease, or (ii) Landlord reasonably
              determines that it will be unable to accommodate the proposed
              assignee's or sublessee's need for space anywhere within the
              Project within three (3) months after the commencement date of the
              proposed assignment or sublease.

          (4) Any other assignment or sublease without the consent of Landlord
              (which may be withheld in Landlord's sole and absolute discretion)
              shall be prohibited.

      (c) Any rent or other consideration realized by Tenant in connection with
          any sublease or assignment (except pursuant to Section 4.05(a)) in
          excess of the Rent payable hereunder, after amortization (over the
          term of such sublease or assignment) of all reasonable costs incurred
          by Tenant in connection with such subletting or assignment (including,
          without limitation, brokerage commissions, legal fees, tenant
          inducements, and reasonable financing charges (the reasonableness of
          which is to be determined with reference to the rates then being
          offered by institutional lenders for such financing)), shall be
          divided and paid as follows: (i) so long as after such assignment or
          subletting Tenant and/or any Tenant Affiliate shall occupy not less
          than seventy-five percent (75%) of the Net Rentable Area included in
          the Leased Premises on the Term Commencement Date, fifty percent (50%)
          of the excess shall be paid to




                                      -34-


<PAGE>



          Tenant and fifty percent (50%) to Landlord; and (ii) in all other
          cases, twenty-five percent (25%) of the excess shall be paid to Tenant
          and seventy-five percent (75%) to Landlord.

      (d) In any subletting undertaken by Tenant, other than subletting to
          Tenant Affiliates or where Landlord agrees to the contrary, Tenant
          shall seek to obtain rent at the market rate for the space so sublet.
          In any assignment of this Lease, other than an assignment to a Tenant
          Affiliate or where Landlord agrees to the contrary, Tenant shall seek
          to obtain from the assignee consideration reflecting rent at the
          market rent for the space subject to such assignment. Tenant shall not
          be obligated to obtain rent at the market rate for the space so sublet
          or assigned.

      (e) In the case of each assignment or sublease: (i) Tenant and the
          assignee or subtenant, as the case may be, shall execute an assignment
          or sublease which shall include terms that do not materially differ
          from those previously disclosed to Landlord; (ii) promptly, but in any
          event within five (5) Business Days after the execution thereof, an
          executed copy of the assignment or sublease shall be delivered to
          Landlord; (iii) the terms and provisions of any sublease whereby the
          sublessee occupies less than seventy-five percent (75%) of the Net
          Rentable Area included in the Leased Premises on the Term Commencement
          Date shall specifically prohibit the assignment of the interest of the
          sublessee, or the sub-subletting of all or any portion of the Leased
          Premises covered by the sublease without the prior written consent of
          the Landlord, which consent shall not be unreasonably withheld; (iv)
          no assignment or sublease shall affect the continuing primary
          liability of Tenant (which, following assignment or sublease, shall be
          joint and several with the assignee or subtenant, as the case may be;
          however, Landlord shall have no obligation to name any such assignee
          or sublessee, in connection with enforcing any of Landlord's rights
          against Tenant hereunder); (v) no consent by Landlord to any of the
          foregoing in the specific instance shall operate as a waiver in any
          subsequent instance; (vi) no assignment or sublease shall permit the
          assignee, sublessee or any other person or entity having an interest
          in the possession, use, occupancy or utilization of the Leased
          Premises, to receive or to pay rental or payment on account of the
          use, occupancy or utilization of the Leased Premises based in whole or
          in part on the net



                                      -35-


<PAGE>



          income or profits derived by any person or entity from any property
          leased, used, occupied or utilized (other than an amount based on a
          fixed percentage or percentages of receipts of sales); and (vii) no
          assignment shall be binding upon Landlord, unless Tenant shall deliver
          to Landlord an instrument in form and in substance reasonably
          satisfactory to Landlord and in recordable form which contains a
          covenant of assumption by the assignee with respect to the period
          following the effective date of the assignment running to Landlord and
          all persons claiming by, through and under Landlord, but the failure
          or refusal of the assignee to execute such instrument of assumption
          shall not release or discharge the assignee from its primary liability
          as Tenant hereunder.

      (f) No assignment or sublease by Tenant shall relieve Tenant of any
          obligation under this Lease. Any assignment or subletting which
          conflicts with the provisions hereof shall be void.

      (g) If Tenant has obtained Landlord's consent to assign this Lease or
          sublet all or any portion of the Leased Premises, and Tenant has
          failed to execute an assignment or sublease within six (6) months
          following the date of Landlord's consent (which is referred to in
          Section 4.05(b) above), Tenant shall again be obligated to notify
          Landlord of any intent to assign this Lease or sublet all or any
          portion of the Leased Premises, and Landlord shall again have the
          right to approve any proposed assignment or sublease under Section
          4.05(b)(1) and (2) above and, if applicable, to terminate this Lease
          as to all or a portion of the Leased Premises in accordance with
          Section 4.05(b)(2) above.

4.06. Alterations and Surrender. Tenant shall not make or allow to be made any
Tenant Alterations in or to the Leased Premises without obtaining the prior
written consent of Landlord, which consent shall not be unreasonably withheld
with respect to proposed alterations and additions which (i) comply with all
applicable laws, ordinances, rules and regulations, (ii) are compatible with the
Building and its mechanical, electrical, HVAC and life safety systems, and do
not excessively burden the capacity of such systems; (iii) do not materially
interfere with the use and occupancy of any other portion of the Building; and
(iv) do not affect the structural integrity of the Building, Specifically, but
without limiting the generality of the foregoing, Landlord's right of consent
shall encompass plans and specifications for proposed alterations or additions,
construction


                                      -36-

<PAGE>




means and methods, the identity of any contractor or subcontractor to be
employed on the work of alterations or additions, and the time for performance
of such work. Tenant shall supply to Landlord any documents and information
reasonably requested by Landlord in connection with its consent hereunder.
Notwithstanding the foregoing, nonstructural Tenant Alterations which do not
impact the Building's mechanical, electrical, HVAC and life safety systems and
which otherwise satisfy the criteria set forth in (i) through (iv) above, and
the other provisions hereof, shall not require Landlord's consent if the cost
thereof does not exceed twenty-five thousand dollars ($25,000), provided,
however, that Tenant shall nonetheless provide written notice of the proposed
alteration, together with plans and specifications therefor (or such other
information in lieu of plans and specifications as Landlord may reasonably
require) at least ten (10) Business Days before undertaking any such work.

Notwithstanding that the same may constitute Building Common Areas, Tenant may
paint or decorate that portion of the Building's fire stairwells located between
floors constituting the Leased Premises, subject to the prior written consent of
Landlord (which shall not be unreasonably withheld).

All Tenant Alterations permitted hereunder shall be made and performed by Tenant
without cost or expense to Landlord, and the work necessary therefor shall be
handled in such a manner as to maintain harmonious labor relations and not
interfere with or delay the work of any contractor employed by Landlord;
provided, however, that Tenant and Landlord shall each use reasonable efforts to
avoid any interference between their respective contractors. Tenant's
contractors, subcontractors and labor shall be subject to reasonable rules and
regulations of the site. If any contractors, subcontractors or labor employed by
or on behalf of Tenant in connection with such Tenant Alterations cause any
dispute, strike or unrest with or amongst other contractors, subcontractors or
labor who may then or thereafter be engaged to work at the Project, Tenant
shall, within two (2) Business Days after written notice to do so by Landlord,
either eliminate the problem or remove the person(s) causing the problem, and
after said two (2) Business Day period, Landlord shall have the right to deny
access to the Project to such person(s). Tenant shall reimburse Landlord upon
demand for any and all costs or expenses incurred by Landlord as a result of
such dispute. Tenant shall take such steps as may be necessary to avoid the
filing, perfection or enforcement of any lien for labor or materials against the
Land or the Building by reason of work performed by or on behalf of Tenant, and
shall cause any such lien to be discharged of record by payment, deposit, order
of court of competent jurisdiction, bonding or other manner reasonably


                                      -37-

<PAGE>



acceptable to Landlord as soon as is reasonably possible but in no event more
than ten (10) Business Days after the first to occur of (i) the date on which
Tenant receives actual notice of the filing thereof, or (ii) the date on which
Landlord gives notice to Tenant of the filing thereof (except where such lien is
filed as a result of the failure of Tenant to pay any contractor, subcontractor
or labor any amount owing to such contractor, subcontractor or labor when due,
or other fault of Tenant, in which case Tenant shall cause such lien to be
discharged as soon as is reasonably possible). Landlord agrees to make
reasonable efforts to cooperate with Tenant as reasonably necessary to discharge
such lien.

Such Tenant Alterations when made to the Leased Premises, together with all
Initial Tenant Improvements, shall become the property of Landlord upon the
termination of this Lease and shall be surrendered to Landlord upon the
termination of this Lease by lapse of time or otherwise; provided, however, that
this clause shall not apply to Tenant's Personal Property and shall not apply to
any Initial Tenant Improvements or Tenant Alterations specified by Tenant in a
notice given to Landlord and approved by Landlord in writing prior to effecting
the same, or which as a condition of approval Landlord specifies that Tenant
remove, and all of Tenant's Personal Property together with any Initial Tenant
Improvements or Tenant Alterations so specified by Landlord or Tenant shall be
removed by Tenant, at Tenant's expense, prior to the expiration of the Term. At
the expiration or termination of this Lease, Tenant shall peaceably yield up the
Leased Premises clean and neat, subject to and in accordance with the
requirements of Section 4.04 (and the obligations of Tenant provided for in this
sentence, and the balance of this paragraph shall survive any expiration or
termination of this Lease). Title to all Tenant Alterations and Initial Tenant
Improvements not removed by Tenant pursuant to the immediately preceding
sentence on or prior to the termination of the Term shall automatically be
conveyed and transferred by Tenant to Landlord upon such expiration or
termination, and shall be deemed abandoned by Tenant and shall thereupon become
the property of Landlord. Tenant shall execute such documentation confirming and
ratifying such conveyance and transfer as Landlord shall reasonably require.
Tenant shall repair at its sole cost and expense, in a manner reasonably
acceptable to Landlord, all damage caused to the Leased Premises or the Building
by removal of Tenant's Personal Property and such Initial Tenant Improvements or
Tenant Alterations as Tenant shall remove or be required to remove as a
condition of approval from the Leased Premises.



                                      -38-

<PAGE>




4.07. Compliance with Laws and Insurance Standards. Tenant shall not permit any
portion of the Leased Premises to be occupied or used for any business or
purpose which is inconsistent with the operation of the Building as a first
class office building in Boston, creates a fire hazard, or would in any way
increase the rate of insurance coverage on the Building and/or its contents. If
Tenant does or permits anything to be done which shall directly increase the
cost of any insurance policy carried hereunder, Landlord shall deliver to Tenant
a written statement setting forth the amount of and reason for any such
insurance cost increase and showing in reasonable detail the manner in which it
has been computed, and Tenant shall, within ten (10) days after receiving such
statement, reimburse Landlord for any such additional premiums. Landlord agrees
that if any other tenant of the Building does or permits anything to be done
which directly increases the cost of any insurance policy carried by Landlord
hereunder, Tenant shall not be required to pay for any portion of such increase
and such increase shall not be included in Operating Costs. Tenant shall comply
with all laws, ordinances, orders, rules and regulations (state, federal,
municipal or promulgated by other agencies or bodies having or claiming
jurisdiction) related to the occupancy, maintenance and repair (unless within
Landlord's obligation under Section 3.01(a)(iii)) of the Leased Premises by
Tenant, and, in pursuance thereof, Tenant shall keep the Leased Premises
equipped with all safety appliances required by any law or ordinance or other
regulation of any public authority because of the manner of use made by Tenant
of the Leased Premises (as distinguished from those required because of the use
of the Leased Premises for the Permitted Use), and shall procure all licenses
and permits required by any law or ordinance or other regulation of any public
authority because of such manner of use, and, if required by Landlord, do any
work required by any law or ordinance or other regulation of any public
authority because of such manner of use, it being understood that the foregoing
provisions shall not be construed to broaden in any way the Permitted Use.
Nothing done by Tenant in the manner of its use or occupancy of the Leased
Premises shall create, require or cause imposition of any requirement by any
public authority for structural or other upgrading of or improvement to the
Building, other than in the Leased Premises provided that any such upgrading is
done at Tenant's sole expense and otherwise in accordance with the provisions
hereof, including Section 4.06.

4.08. Entry for Repairs and Leasing. After reasonable notice (but not more than
two (2) Business Days notice (excluding the day such notice is given), except in
emergencies, when no such notice shall be required), Landlord, its agents and
representatives, shall have the right to enter the Leased Premises to inspect
the same, to exercise such rights as may be permitted hereunder, to


                                      -39-

<PAGE>




make repairs to the Building or alterations required for the Building or other
tenant spaces therein, to deal with emergencies, or to exhibit the Leased
Premises to prospective tenants (during the last two (2) years of the Term),
purchasers, encumbrancers or others, or for any other purpose as Landlord may
deem necessary or desirable; provided, however, that Landlord shall use
reasonable efforts not to unreasonably interfere with Tenant's business
operations. Tenant shall not be entitled to any abatement of Rent by reason of
the exercise of any such right of entry.

4.09. No Nuisance. Tenant shall conduct its business and control its agents,
employees, invitees and visitors in such manner as not to create any nuisance,
or unreasonably interfere with or disturb any other tenant or Landlord in its
operation of the Building.

4.10. Subordination. This Lease and the rights of Tenant hereunder shall be
subject and subordinate to any Mortgage, and to any and all advances made
thereunder, interest thereon or costs incurred in connection therewith, so long
as in connection therewith the holder of any such Mortgage and Tenant shall have
executed an agreement in commercially reasonable form and substance (with due
weight being given to the amount of space then being leased by Tenant) which
provides, inter alia, (i) that so long as this Lease is in full force and effect
and there exists no Event of Default hereunder, Tenant's rights under this Lease
shall not be disturbed by reason of such subordination or by reason of
foreclosure of such Mortgage, or exercise of the statutory power of sale, or
receipt of a deed in lieu of foreclosure, and (ii) that Tenant shall attorn to
the holder or the purchaser at any such sale or foreclosure or the grantee of
any such deed. Until the holder of such Mortgage shall enter into actual
possession of the Leased Premises, such holder shall not be liable to perform
any of the obligations of Landlord hereunder. In the event of attornment by
Tenant pursuant to the provisions of this Section 4.10, this Lease shall
continue in full force and effect as a direct lease between such mortgagee,
purchaser or grantee, as a successor landlord, and Tenant, upon all the terms,
conditions and covenants set forth herein (including, without limitation, the
obligation of Landlord to provide Basic Services pursuant to Section 3.01(a)),
except that such mortgagee, purchaser or grantee (unless formerly the Landlord
under this Lease) shall not be (a) bound by any payment of Rent for more than
one month in advance; (b) bound by any amendment of modification of this Lease
made without the consent of the holder of the Mortgage; (c) liable in any way to
Tenant for any act or omission, neglect or default on the part of Landlord under
this Lease, (d) obligated to perform any tenant improvements to be done by
Landlord in the Leased Premises (other than the Initial Tenant Improvements), or
(e) subject to any counterclaim or set-off which theretofore



                                      -40-

<PAGE>




accrued to Tenant against Landlord. Without the consent of Tenant, the holder of
any such Mortgage shall have the right to elect to be subject and subordinate to
this Lease, such subordination to be effective upon such terms and conditions as
such holder may direct which are consistent with the provisions hereof.

4.11. Estoppel Certificate. At Landlord's request, Tenant shall execute,
acknowledge and deliver (within ten (10) Business Days after Tenant receives any
such request) estoppel certificates on a form specified by Landlord, addressed
to (i) any mortgagee or prospective mortgagee of Landlord or (ii) any purchaser
or prospective purchaser of all or any portion of, or interest in the Building,
certifying as to such facts (if true) and agreeing to such notice provisions and
other matters as such mortgagee(s) or purchaser(s) may reasonably require;
provided, however, that in no event shall any such estoppel certificate require
an amendment of the provisions hereof or otherwise affect or abridge Tenant's
rights hereunder. At Tenant's request, Landlord shall execute, acknowledge and
deliver (within ten (10) Business Days after Landlord receives any such request)
an estoppel certificate certifying (a) that this Lease is in full force and
effect, or is in full force and effect as modified and stating any
modifications, (b) whether or not, to the best of Landlord's knowledge, Tenant
is in default hereunder, and (c) such other matters as Tenant may reasonably
request. All requests for estoppel certificates pursuant to this Section 4.11,
whether by Landlord or Tenant, shall specifically reference this Section 4.11
and the ten (10) Business Day period set forth herein.

4.12. Tenant's Remedies. Tenant shall look solely to Landlord's interest in the
Building for recovery of any judgment from Landlord. Notwithstanding the
foregoing, in the event Landlord intends (whether or not voluntarily) to
transfer its interest in the Building, Landlord shall notify Tenant of such
intended transfer ("Landlord's Transfer Notice"), exercising reasonable efforts
to do so on the date which is thirty (30) days prior to the date of closing, but
in any event no later than the date of closing. With respect to any claim which
Tenant knows it may then have against Landlord which is set forth in a notice
given to Landlord within thirty (30) days of Landlord's Transfer Notice (the
"Initial Claim Period"), or, with respect to claims Tenant becomes aware of
after the date Landlord's Transfer Notice is given and which are set forth in a
notice given to Landlord during the period from the date upon which Landlord's
Transfer Notice is given to the date of closing (the "Extra Claim Period"),
Landlord's liability for any such claim shall not be limited to Landlord's
interest in the Building, but may also be satisfied out of the proceeds of such
transfer net of all reasonable costs



                                      -41-

<PAGE>




incurred in connection with such transfer (but not out of any other assets of
Landlord). In the event Tenant fails to give such notice to Landlord within said
Initial Claim Period or Extra Claim Period, as the case may be, Tenant shall be
deemed to have waived the rights granted with respect to such claims under this
Section 4.12. in the event of any transfer by Landlord of its interest in the
Building to an affiliate with the intent to hinder, delay or defraud Tenant with
respect to such claim, then notwithstanding such transfer and the provisions of
Section 8.03 to the contrary, Tenant shall be entitled to look to the Building
for recovery of such claim irrespective of the fact that Landlord shall have no
further interest therein. Landlord, its agents, employees, and, if Landlord is a
partnership, its partners, whether general or limited, or if Landlord is a
corporation, its directors, officers or shareholders, shall never be personally
liable for any such judgment. Any lien obtained to enforce any such judgment and
levy of execution thereon shall be subject and subordinate to any Mortgage.

4.13. Rules and Regulations. Tenant shall comply with the rules and regulations
for the Building attached as Exhibit D and such reasonable amendments thereto as
Landlord may adopt from time to time with prior notice to and consultation with
Tenant. Nothing contained in the Rules and Regulations shall preempt the rights
expressly granted to Tenant under this Lease. All rules and regulations shall be
enforced Building-wide in a nondiscriminatory manner.

4.14. Personal Property at Tenant's Risk. All of Tenant's Personal Property
shall be at the sole risk and hazard of Tenant, and if the whole or any part
thereof shall be destroyed or damaged by fire, water or otherwise, by the
leakage or bursting of water pipes, steam pipes or other pipes, or by theft or
from any other cause, no part of said loss or damage is to be charged to or be
borne by Landlord, except Landlord shall in no event be held harmless or
exonerated for any liability to Tenant or to any other person, for any injury,
loss, damage or liability to the extent caused by the negligence or willful
misconduct of Landlord or any Landlord Responsible Party.

4.15. Payment of Landlord's Expenses. Tenant shall pay, as Additional Rent, all
reasonable costs, including without limitation counsel and other fees incurred
by Landlord in connection with all requests by Tenant for consent or approval
hereunder (to the extent such costs are not ordinary and usual costs associated
with the ownership or management of the Building which are included as part of
the Operating Cost), and/or the successful enforcement by Landlord of any
obligation of Tenant under this Lease. Landlord agrees that any such costs
incurred by


                                      -42-

<PAGE>




Landlord in connection with other tenants of the Building shall be paid by such
party and not by Tenant (except to the extent such costs are ordinary and usual
costs associated with the ownership management of the Building which are
included as part of the Operating Cost).

4.16. Window Coverings. Tenant shall not place or maintain any window coverings,
blinds or drapes (other than those supplied by Landlord) on any exterior window
of the Building or on any interior window facing the "Winter Garden" without
Landlord's prior approval, which may be withheld in Landlord's absolute and sole
discretion. Tenant shall not place any furniture or equipment of any kind within
two (2) feet of the interior surface of any interior window facing the Winter
Garden (other than chairs or similar moveable furniture temporarily located
within said two (2) foot area) and Tenant shall at all times maintain such
interior windows so as to preserve the visual aesthetics of the Winter Garden.
Landlord agrees to impose the requirements of this Section 4.16 upon all other
applicable tenants of the Building and to enforce such provisions in a uniform
manner.


                                    ARTICLE 5

                           CASUALTY and EMINENT DOMAIN
                           ---------------------------


5.01. Casualty Insurance. Landlord shall maintain, or cause to be maintained, a
policy or policies of insurance with the premiums thereon fully paid in advance,
issued by and binding upon an insurance company of good financial standing,
insuring the Building and the Project Common Areas against loss or damage by
fire or other insurable hazards and contingencies as are covered in the usual
standard extended coverage endorsement or all-risks endorsement, for one hundred
percent (100%) of the replacement cost of the Building and for ninety percent
(90%) of the replacement cost of the Project Common Areas (excluding, however,
the foundation and footings of the Building and a reasonable deductible);
provided, that Landlord shall not be obligated to insure any of Tenant's
Personal Property, or any Tenant Improvements in excess of the Building Standard
Improvements. If the annual premiums charged Landlord for such casualty
insurance exceed the standard premium rates because the nature of Tenant's
operations results in extra-hazardous exposure, then Tenant shall, upon receipt
of appropriate premium invoices, reimburse Landlord for such increases in
premium as Additional Rent. Landlord agrees that any such costs incurred by
Landlord in connection with other tenants of the Building shall not be included
as an Operating Cost, and shall not be charged to Tenant. Upon the request of

                                      -43-

<PAGE>



Tenant, Landlord shall provide Tenant with a certificate of such insurance. Any
such insurance may be maintained by Landlord under blanket policy or policies;
provided, however, that the minimum amount of the total insurance afforded by
such blanket policy Which shall be allocated to the Building and the Project
Common Areas and any sublimits of such policy allocable to the Building and the
Project Common Areas, shall be in amounts which shall not be less than the
amounts of insurance required hereunder and the protection afforded Landlord
under such policy shall be not less than that which would have been afforded
under a separate policy relating only to the Building and the Project Common
Areas and the certificate evidencing such insurance shall contain provisions
confirming the foregoing.

5.02. Liability Insurance. Landlord (with respect to the Building) and Tenant
(with respect to the Leased Premises and the Building) shall maintain or cause
to be maintained a policy or policies of comprehensive general liability
insurance with the premiums thereon fully paid in advance issued by and binding
upon an insurance company of good financial standing, such insurance to afford
minimum protection of not less than Three Million Dollars ($3,000,000.00) for
personal injury or death in any one occurrence and of not less than Five Hundred
Thousand Dollars ($500,000.00) for property damage in any one occurrence. Such
insurance shall be written on an occurrence basis and the coverages required to
be carried thereunder shall be extended to include blanket contractual
liability, personal injury liability (libel, slander, false arrest and wrongful
eviction), and broad form property damage liability. The insurance carried by
Tenant pursuant to this Section 5.02 shall specifically recognize the liability
assumed by Tenant under this Lease and shall provide that where insurance
coverage is provided under more than one policy, Tenant's insurance is primary,
and any other insurance available to Landlord or any other named insured is
excess. Upon request of either party, the other party shall provide reasonable
evidence that the insurance required to be maintained hereunder is in full force
and effect (it being understood and agreed that the foregoing obligation to
provide evidence of insurance is in addition to any obligation to provide
certificates pursuant to Section 5.01 or Section 5.03).

5.03. Tenant's Insurance.

      (a) Tenant shall carry the comprehensive general liability insurance
          required by Section 5.02 hereof and shall also carry fire and extended
          coverage insurance on Tenant's Personal Property in the Leased
          Premises in the amount of their full replacement cost (subject only to
          a reasonable deductible and co-insurance factor). In



                                      -44-

<PAGE>



          addition, Tenant shall maintain workers' compensation insurance and
          all such other insurance relating to Tenant's use and occupancy of the
          Leased Premises and the Building as may be required by applicable law.
          All such policies required to be carried by Tenant hereunder and all
          evidence of insurance provided to Landlord shall be issued by
          responsible, financially sound companies qualified to do business and
          in good standing in the Commonwealth of Massachusetts and shall
          contain an endorsement showing that Landlord and each holder of a
          Mortgage (disclosed in writing to Tenant) is included as an additional
          insured (except as to workers' compensation insurance), as its
          interests may appear and an endorsement whereby the insurer agrees not
          to cancel or alter the policy without at least thirty (30) days prior
          written notice to Landlord, to the holder of such Mortgage and all
          other named insureds. Tenant shall, on or prior to occupying any
          portion of the Leased Premises, deposit with Landlord certificates of
          such insurance, and thereafter, on or prior to fifteen (15) days
          before the expiration date of any coverage thereunder, shall deposit
          with Landlord certificates evidencing the renewal of such policies.
          Any such insurance may be maintained by Tenant under a blanket policy
          or policies; provided, however, that the minimum amount of the total
          insurance afforded by such blanket policy which shall be allocable to
          the Leased Premises and any sublimits of such policy allocable to the
          Leased Premises, shall be in amounts which shall not be less than the
          amounts of the insurance required hereunder, and the protection
          afforded to Landlord and each holder of a Mortgage under such policy
          shall be not less than that which would have been afforded under a
          separate policy or policies relating only to the Leased Premises, and
          the certificate evidencing such insurance shall contain provisions
          confirming the foregoing.

      (b) In the event that Tenant fails to timely furnish Landlord evidence of
          the insurance required to be provided by Tenant pursuant to Subsection
          (a) above, and such failure shall continue for five (5) Business Days
          after notice thereof from Landlord, Landlord shall be authorized (but
          not required) to procure such coverage in the amounts stated with all
          costs thereof to be chargeable to Tenant as Additional Rent, and
          payable by Tenant upon receipt of written invoice therefor.






                                      -45-

<PAGE>




5.04. Indemnity and Exoneration. Except to the extent such indemnity or
exoneration is prohibited by law or as otherwise expressly provided in this
Lease,

      (a) Landlord shall not be liable to Tenant for injury to any person or any
          loss or damage to any property or any inconvenience caused by (i)
          theft, burglary or acts of unauthorized persons in or about the
          Building, or (ii) any act of Force Majeure, any repair or alteration
          of any part of the Building, or any failure to make any such repair,
          except in each case to the extent the same is caused by the negligence
          or willful misconduct of Landlord or any Landlord Responsible Party;

      (b) Tenant shall indemnify Landlord and hold Landlord harmless of and from
          any and all loss, cost, damage, injury or expense arising out of or
          related to claims of injury to or death of persons or damage to
          property occurring upon, or resulting from the use or occupancy of,
          the Leased Premises or the Building by Tenant, or resulting from
          activities of Tenant in or about the Leased Premises or the Building,
          such indemnity to include, without limitation, the obligation to
          provide all costs of defense against any such claims, except in each
          case to the extent the same is caused by the negligence or willful
          misconduct of Landlord or any Landlord Responsible Party;

      (c) Tenant shall hold and save Landlord harmless and indemnify Landlord of
          and from any and all loss, cost, damage, injury or expense arising out
          of or in any way related to claims for work or labor performed,
          materials or supplies furnished to or at the request of Tenant or in
          connection with performance of any work done for the account of Tenant
          in the Leased Premises or the Building, excluding all Tenant Initial
          Improvements, such indemnity to include, without limitation, the
          obligation to provide all costs of defense against any such claim; and

      (d) Landlord shall indemnify Tenant and hold Tenant harmless of and from
          any loss, cost, damage, injury or expense incurred by Tenant in
          connection with injury to or death of persons or damage to property
          occurring upon the Leased Premises or the Building to the extent the
          same is caused by the negligence or willful misconduct of Landlord or
          any Landlord Responsible Party, or as a result of any claim asserted
          against Tenant by the City of Boston or any other governmental
          authority based on



                                      -46-


<PAGE>



          any alleged noncompliance of the Leased Premises or the Building with
          any applicable building codes or regulations in effect on the
          Completion Date, such indemnity to include, without limitation, the
          obligation to provide all costs of defense against any such claim;
          provided that Landlord shall not be responsible for any noncompliance
          of Tenant Alterations.

5.05. Waiver of Subrogation Rights. Anything in this Lease to contrary
notwithstanding, to the extent any claim is covered by casualty insurance, or
should be covered by any required casualty insurance, Landlord and Tenant each
waive all rights of recovery, claim, action or cause of action against the
other, its agents (including partners both general and limited), officers,
directors, shareholders or employees, for any loss or damage that may occur to
the Leased Premises, or any improvements thereto, to the Building or to any
personal property of such party therein, by reason of fire, the elements, or any
other cause which are required to be insured against under the terms of such
insurance policies, or any other peril which is in fact insured, regardless of
cause or origin, including negligence of the other party hereto, its agents,
officers or employees; and each party covenants that no insurer shall hold any
right of subrogation against such other party. Each party shall advise insurers
of the foregoing and such waiver shall be a part of each applicable policy
maintained by Landlord and/or Tenant which applies to the Leased Premises, any
part of the Building or Tenant's use and occupancy of any part thereof; provided
that this waiver shall be null and void if the affected insurer refuses to
consent to such waiver, and provided further that all costs (if any) associated
with obtaining insurer consent shall be borne by the party benefited by such
waiver, unless such party elects to waive the benefit of such provision.

5.06. Condemnation and Loss or Damage.

      (a) If all or any portion of the Leased Premises or the Building shall be
          taken or condemned for any public purpose to such an extent as to
          render the Leased Premises untenantable as reasonably determined by
          either Landlord or Tenant, this Lease shall, at the option of either
          party (provided such option shall be exercised by the giving of notice
          by the exercising party to the other party within sixty (60) days from
          the date the exercising party has been notified of such taking or
          condemnation) forthwith cease and terminate as of the date of the
          taking. If this Lease is not terminated in accordance with the
          provisions of this subparagraph (a), the Rent due shall be abated in
          proportion to the


                                      -47-

<PAGE>




          portion of the Leased Premises so taken, and Landlord shall be
          obligated to repair and restore the Leased Premises and/or the
          Building and shall proceed diligently to do so; provided, however,
          that Landlord shall have no obligation to incur costs to repair and
          restore the Leased Premises and/or the Building which exceeds the
          amount of condemnation proceeds Landlord realizes or any insurance
          proceeds which, as a result of such taking, Landlord realizes or would
          have realized had Landlord procured the insurance required by Section
          5.01, and provided further Landlord shall have no obligation to repair
          and restore any Tenant Alterations, Excess Building Standard
          Improvements or Premium Tenant Improvements to the extent the same
          were paid for by Tenant. All proceeds from any taking or condemnation
          of the Leased Premises shall belong to and be paid to Landlord, and
          Tenant hereby assigns to Landlord its interest in said proceeds,
          subject to the rights of any holder of any Mortgage; provided,
          however, Tenant shall be entitled to any proceeds attributable to
          Tenant Alterations, Excess Building Standard Improvements or Premium
          Tenant Improvements to the extent the same were paid for by Tenant,
          and provided further Landlord shall cooperate with Tenant if Tenant
          seeks to recover, at its cost and expense, compensation for its moving
          expenses and personal property. In no event shall any such recovery by
          Tenant have the effect of diminishing or delaying the award payable to
          Landlord on account of any taking or condemnation.

      (b) In the event of a temporary taking of all or any portion of the Leased
          Premises, the Rent due shall be abated in proportion to the portion of
          the Leased Premises so taken. In such event, Landlord shall be
          obligated to restore the Building and the Leased Premises as may
          reasonably be required as a result of such taking and shall proceed
          diligently to do so; provided, however, that Landlord shall have no
          obligation to incur costs to repair and restore the Leased Premises
          and/or the Building which exceeds the amount of condemnation proceeds
          Landlord realizes or any insurance proceeds which Landlord realizes or
          would have realized had Landlord procured the insurance required by
          Section 5.01, and provided further Landlord shall have no obligation
          to repair and restore any Tenant Alterations, Excess Building Standard
          Improvements or Premium Tenant Improvements to the extent the same
          were paid for by Tenant.



                                      -48-

<PAGE>




5.07. Damage Due to Fire and Casualty. In the event of a fire or other casualty
in the Leased Premises, Tenant shall immediately have notice thereof to
Landlord. In the event of any fire or other casualty in the Building, the
following provisions shall apply:

      (a) Unless either Landlord or Tenant is entitled to terminate this Lease
          pursuant to subparagraphs (b), (c) or (d) below, and this Lease is so
          terminated, Landlord shall be obligated to repair and restore the
          Leased Premises and/or the Building and shall proceed diligently to do
          so; provided, however, that Landlord shall have no obligation to incur
          costs to repair and restore the Leased Premises and/or the Building
          which exceed the amount of insurance proceeds which Landlord realizes
          (or would have realized had Landlord procured the insurance required
          by Section 5.01) for such purpose plus an amount equal to (a) any
          deductible for such insurance and (b) with respect to the Project
          Common Areas only, if one hundred percent (100%) replacement cost
          coverage was not obtained with respect thereto, the difference between
          the proceeds of the replacement cost insurance actually obtained and
          the proceeds which would have been obtained from one hundred percent
          (100%) replacement cost coverage.

      (b) If, at the time a fire or other casualty occurs, there remains less
          than twenty-four (24) months in the Term, and if Landlord reasonably
          estimates that upon completion of the repairs and restoration with
          substantially all damage repaired less than six (6) months will remain
          in the Term, Landlord shall, within forty-five (45) days after the
          occurrence of the fire or other casualty give Tenant notice either (i)
          setting forth the reasons for Landlord's determination and eliminating
          from the Leased Premises, those full floors, if any, which incurred
          substantial damage, or (ii) offering Tenant the option of either (x)
          electing to eliminate from the Leased Premises those full floors which
          incurred substantial damage, or (y) terminating this entire Lease by
          notice to Landlord given during the thirty (30) day period following
          the date Landlord's notice is given.

      (c) Subject to the provisions of paragraph (b) above, if the damage caused
          by such fire or other casualty renders untenantable either (i) fifty
          percent (50%) or more of





                                      -49-

<PAGE>




          the Net Rentable Area of the Leased Premises, or (ii) twenty-eight
          percent (28%) or more of the Net Rentable Area of the Office Section
          (including some portion of the Office Section outside of the Leased
          Premises) then, if:

          (x) such untenantable space cannot, in Landlord's reasonable judgment,
              be made tenantable with substantially all damage repaired within
              twelve (12) months of the occurrence of the fire or other
              casualty, but can be so repaired or restored within eighteen (18)
              months thereof, then

              (I) if at least twelve (12) months will remain in the Term after
                  completion of such repair, Landlord shall give Tenant notice
                  within forty-five (45) days after the date of such fire or
                  other casualty, following which Tenant shall, within thirty
                  (30) days of the date Landlord's notice is given, give
                  Landlord notice either (i) terminating this Lease, or (ii)
                  electing not to terminate this Lease; and

             (II) if less than twelve (12) months will remain in the Term after
                  completion of such repair, Landlord shall, within forty-five
                  (45) days after the date of such fire or other casualty, give
                  Tenant notice (A) setting forth the reasons for Landlord's
                  determination and, if all other leases in the Building are to
                  be terminated as a result thereof, terminating this Lease, (B)
                  setting forth the reasons for Landlord's determination and, if
                  all other leases in the Building are not going to be
                  terminated as a result thereof, eliminating from the Leased
                  Premises those full floors, if any, which incurred substantial
                  damage, or (C) offering Tenant the option of (m) electing to
                  eliminate from the Leased Premises those full floors which
                  incurred substantial damage, or (n) terminating this entire
                  Lease by notice to Landlord given during the thirty (30) day
                  period following the date Landlord's notice is given;

          (y) such untenantable space cannot, in Landlord's reasonable judgment,
              be made tenantable with substantially all damage repaired within
              eighteen (18) months of the occurrence of the fire or other



                                      -50-

<PAGE>




              casualty, but at least seventy-five percent (75%) of the Net
              Rentable Area of the Leased Premises is or can be made tenantable
              with substantially all damage repaired within such eighteen (18)
              month period, and at least twelve (12) months will remain in the
              Term after completion of such repair, then Landlord shall notify
              Tenant within forty-five (45) days after the date of such fire or
              other casualty, following which Tenant shall, within thirty (30)
              days of the date Landlord's notice is given, give Landlord notice
              (i) electing to eliminate from the Leased Premises those full
              floors which cannot be made tenantable within such eighteen (18)
              month period, (ii) terminating this entire Lease, or (iii)
              electing not to terminate this Lease; and

          (z) notwithstanding the foregoing, (I) at least seventy-five percent
              (75%) of the Net Rentable Area of the Leased Premises cannot be
              made tenantable with substantially all damage repaired within
              eighteen (18) months following the fire or other casualty or (II)
              even if at least seventy-five percent (75%) of the Net Rentable
              Area of the Leased Premises can be made tenantable with
              substantially all damage repaired within such eighteen (18) month
              period but less than twelve (12) months will remain in the Term
              after the completion of such repair, then Landlord shall notify
              Tenant within forty-five (45) days after the date of the fire or
              other casualty, and either Landlord or Tenant may terminate this
              Lease within thirty (30) days of the date Landlord's notice is
              given.

      (d) If Landlord is obligated to restore the Leased Premises or the
          Building in accordance with subparagraph (a) above, and Landlord has
          not commenced restoration within six (6) months from the date of
          damage or destruction, Tenant may terminate this Lease, such
          termination right to be exercised by notice to Landlord within thirty
          (30) days after such right accrues.

      (e) During any period when Tenant's use of the Leased Premises is
          materially affected by damage or destruction, Gross Rent shall abate
          proportionately until such time as the Leased Premises are made
          tenantable as reasonably determined by Landlord and no portion of the
          Rent so abated shall be subject to subsequent recapture, except from
          the proceeds of

                                      -51-

<PAGE>



          insurance policies maintained by Landlord covering such lost Rent, if
          any.

      (f) The proceeds from any insurance paid by reason of damage to or
          destruction of the Building or any part thereof, the Building Standard
          Improvements or any other element, component or property insured by
          Landlord shall belong to and be paid to Landlord, subject to the
          rights of the holder of any Mortgage, and Tenant hereby assigns to
          Landlord any interest in said proceeds.

                                    ARTICLE 6

                                     DEFAULT
                                     -------

6.01. Events of Default. The occurrence of any of the following shall constitute
an "Event of Default" on the part of Tenant:

      (a) Nonpayment of Gross Rent. Failure to pay any regularly scheduled
          payment of Gross Rent due and payable hereunder, upon the date when
          payment is due, such failure continuing for a period of five (5)
          Business Days after notice of such failure; provided, however, that
          Landlord shall not be required to provide such notice more than twice
          during any consecutive twenty-four (24) month period within the Term
          and the third and any subsequent such non-payment occurring within the
          same twenty-four (24) month period shall constitute an Event of
          Default without requirement of notice;

      (b) Nonpayment of Other Amounts. Failure to make any other payment due and
          payable hereunder, upon the date when payment is due, such failure
          continuing for a period of ten (10) Business Days after written notice
          of such failure;

      (c) Other Obligations. Failure to perform any other obligation, agreement
          or covenant under this Lease, other than those matters specified in
          Section 6.01(a) or (b), such failure continuing for fifteen (15)
          Business Days after notice of such failure (or such longer period as
          is reasonably necessary to remedy such default, provided that Tenant
          shall within such fifteen (15) Business-Day period have commenced such
          remedy and thereafter Tenant shall continuously and diligently pursue
          such remedy at all times until such default is cured);


                                      -52-

<PAGE>




      (d) Abandonment. Abandonment of more than 40,000 square feet of Net
          Rentable Area of the Leased Premises during the Term, unless, within
          ten (10) days after such abandonment, Tenant shall have indicated an
          intention to itself to reoccupy the entire Leased Premises within one
          hundred and twenty (120) days (or if such reoccupancy shall include
          occupancy by subtenants or assignees in accordance with Section 4.05
          hereof, within one hundred and eighty (180) days), or the failure of
          Tenant to so reoccupy the entire Leased Premises within said one
          hundred and twenty (120) day period (or, in the case of occupancy by
          subtenants or assignees, within said one hundred and eighty (180) day
          period). Tenant shall be deemed to have abandoned the Leased Premises
          if the Leased Premises remain substantially vacant or unoccupied to an
          extent that might reasonably jeopardize the validity of insurance
          coverage thereon;

      (e) General Assignment. A general assignment by Tenant for the benefit of
          creditors;

      (f) Bankruptcy. The filing of any voluntary petition in bankruptcy by
          Tenant, or the filing of an involuntary petition by Tenant's
          creditors, which involuntary petition remains undischarged or unstayed
          for a period of one hundred and eighty (180) days. In the event that
          under applicable law the trustee in bankruptcy or Tenant has the right
          to affirm this Lease and continue to perform the obligations of Tenant
          hereunder, such trustee or Tenant shall, in such time period as may be
          permitted by the bankruptcy court having jurisdiction, cure all
          defaults of Tenant hereunder outstanding as of the date of the
          affirmance of this Lease and provide to Landlord such adequate
          assurances as may reasonably be necessary to ensure Landlord of the
          continued performance of Tenant's obligations under this Lease;

      (g) Receivership. The employment of a receiver to take possession of
          substantially all of Tenant's assets or the Leased Premises, if such
          receivership remains undissolved for a period of ninety (90) days
          after creation thereof;

      (h) Attachment. The attachment, execution or other judicial seizure of all
          or substantially all of Tenant's assets or the Leased Premises, if
          such attachment or other seizure remains undismissed or undischarged
          for a period of ninety (90) days after the levy thereof;


                                      -53-

<PAGE>




      (i) Insolvency. The admission by Tenant in writing of its inability to pay
          its debts as they become due, the filing by Tenant of a petition
          seeking any reorganization, arrangement, composition, readjustment,
          liquidation, dissolution or similar relief under any present or future
          statute, law or regulation, the filing by Tenant of an answer
          admitting or failing timely to contest a material allegation of a
          petition filed against Tenant in any such proceeding or, if within one
          hundred and eighty (180) days after the commencement of any proceeding
          against Tenant seeking any reorganization, or arrangement,
          composition, readjustment, liquidation, dissolution or similar relief
          under any present or future statute, law or regulation, such
          proceeding shall not have been dismissed.

6.02. Remedies upon Default.

      (a) If an Event of Default occurs, Landlord shall have the right, with or
          without notice or demand, immediately to terminate this Lease, and at
          any time thereafter recover possession of the Leased Premises or any
          part thereof and expel and remove therefrom Tenant and any other
          person occupying the same, by any lawful means, and again repossess
          and enjoy the Leased Premises without prejudice to any of the remedies
          that Landlord may have under this Lease, or at law or equity by reason
          of Tenant's default or of such termination.

      (b) Even though an Event of Default shall have occurred pursuant to
          Section 6.01, this Lease shall continue in effect and Tenant shall
          have the right to cure any such Event of Default for so long as
          Landlord does not terminate this Lease under Section 6.02(a) hereof,
          and Landlord may enforce all of its rights and remedies under this
          Lease, including, without limitation, the right to recover Rent as it
          becomes due. Acts of maintenance, preservation or efforts to lease the
          Leased Premises or the appointment of a receiver upon application of
          Landlord to protect Landlord's interest under this Lease shall not
          constitute an election to terminate the Lease.

6.03. Damages upon Termination. Should Landlord terminate this Lease pursuant to
the provisions of Section 6.02(a) hereof, in addition to any other rights and
remedies to which Landlord may be entitled under applicable law, Landlord shall
be entitled to recover from Tenant: (i) the worth at the time of award of the



                                      -54-

<PAGE>




unpaid Rent and other amounts which had been earned at the time of termination;
(ii) the worth at the time of award of the amount by which the unpaid Rent which
would have been earned after termination until the time of award exceeds the
amount of such Rent loss that the Tenant proves could have been reasonably
avoided; (iii) the worth at the time of award of the amount by which the unpaid
Rent for the balance of the Term after the time of award exceeds the rental
value of the Premises for the balance of the Term; and (iv) any other amount
necessary to compensate Landlord for all the detriment proximately caused by
Tenant's failure to perform its obligations under this Lease. Tenant further
covenants, as an additional cumulative obligation after any such termination, to
punctually pay to Landlord all sums and perform all obligations which Tenant
covenants in this Lease to pay and to perform, as if this Lease had not been
terminated, whether or not such obligations arose prior to, concurrent with or
after such termination. In calculating the amounts to be paid by Tenant pursuant
to the immediately preceding sentence, Tenant shall be credited with any amount
paid to Landlord pursuant to the first sentence of this Section 6.03, and also
with the net proceeds of any rent obtained by Landlord by reletting the Leased
Premises through the time of award, after deducting all Landlord's expenses in
connection with such reletting, including without limitation, all repossession
costs, brokerage commissions, fees for legal services and expenses of preparing
the Leased Premises for reletting, it being agreed by Tenant that Landlord may
(x) relet the Leased Premises or any part thereof for a term or terms which may
at Landlord's option be equal or less than or exceed the period which would
otherwise have constituted the balance of the Term and may grant such
concessions and free rent as Landlord in its exercise of business judgment
considers advisable or necessary to relet the same and (y) make such
alterations, repairs and decorations in the Leased Premises and the Building as
Landlord in its sole judgment considers advisable or necessary to relet the
same, and no action of Landlord in accordance with the foregoing or failure to
relet or collect rent under Landlord's reletting of the Premises shall operate
or be construed to release or reduce Tenant's liability as aforesaid unless and
to the extent Tenant proves such failure could reasonably have been avoided. The
"time of award" shall refer to such time as (I) Tenant shall, as a settlement of
the amounts due pursuant to this Section 6.03, pay to Landlord such sums
pursuant to a written agreement in form and substance satisfactory to Landlord,
or (II) the date on which a Judgment shall be entered in a court of competent
jurisdiction to the effect that Tenant shall pay Landlord the amounts due and
owing pursuant to this Section 6.03. The "worth at the time of award" of the
amounts referred to in (i) and (ii) shall mean such amounts together with
interest at the lesser of eighteen percent per annum or the maximum rate allowed
by law. The "worth at


                                      -55-

<PAGE>




the time of award" of the amount referred to in (iii) shall mean such amounts as
computed by reference to competent appraisal evidence or the formula prescribed
by and using the lowest discount rate utilized by commercial appraisers in
calculating such amounts for such purpose.

6.04. Computation of Rent for Purposes of Default. For purposes of computing
unpaid Rent which would have accrued and become payable under this Lease for the
balance of the Term pursuant to the provisions of Section 6.03, unpaid Rent
shall consist of the sum of:

      (a) the total Net Rent for the balance of the Term, plus

      (b) a computation of the Operating Cost and Impositions for the balance of
          the Term, the assumed Operating Cost for the calendar year of the
          default and each future calendar year in the Term to be equal to the
          Operating Cost for the calendar year prior to the year in which the
          default occurs compounded at a per annum rate equal to the mean
          average rate of inflation for the preceding five (5) calendar years as
          determined by the United States Department of Labor, Bureau of Labor
          Statistics Consumer Price Index (All Urban Consumers, All Items,
          1982-1984 equals 100). If such Index is discontinued or revised, the
          average rate of inflation shall be determined by reference to the
          index designated as the successor or substitute index by the
          government of the United States.

6.05. Rights of Landlord in Bankruptcy. Nothing contained in this Lease shall
limit or prejudice the right of Landlord to prove for and obtain in proceedings
for bankruptcy or insolvency, by reason of the termination of this Lease, an
amount equal to the maximum allowed by any statute or rule of law in effect at
the time when, and governing the proceedings in which, the damages are to be
proved, whether or not the amount be greater, equal to, or less than the amount
of the loss or damages referred to in this Article 6.

6.06. Interest on Late Payments. In addition to its other remedies, Landlord
shall have the right to add to the amount of any payment required to be made by
Tenant hereunder, and which is not paid on or before the date the same is due,
interest on all unpaid payments at the rate of six percent (6%) per annum over
the prime rate of the Bank of Boston, or any successor institution thereto, for
so long as the delinquency remains outstanding, the parties agreeing that
Landlord's damage by virtue of such delinquencies would be difficult to compute
and the amount stated


                                      -56-

<PAGE>




herein represents a reasonable estimate thereof. All such interest charges shall
be due upon demand by Landlord. Tenant shall reimburse Landlord for all costs
and expenses (including reasonable attorneys' fees) incurred by Landlord to
recover the interest charges due hereunder.

                                    ARTICLE 7

                                    APPRAISAL
                                   ----------

7.01. Appraisal of Fair Market Net Rent. In the event that Tenant disputes the
amount claimed by Landlord as Fair Market Net Rent, and such dispute cannot be
resolved by mutual agreement, the dispute shall be submitted to the appraisal
process hereinafter set forth. The amount of Fair Market Net Rent determined
pursuant to such appraisal process shall be final and binding between the
parties. The appraisal process shall be conducted as follows:

      (a) Tenant shall make demand for appraisal in writing within thirty (30)
          days after service of Landlord's determination of Fair Market Net Rent
          given under Section 9.02 or Section 10.04 or otherwise under this
          Lease, specifying therein the name and address of the person to act as
          the appraiser on its behalf. The appraiser shall be a real estate
          appraiser with at least ten (10) years' experience in the leasing or
          appraisal of first-class commercial office space (with at least five
          (5) years experience in Boston) and a qualified member of the American
          Institute of Real Estate Appraisers, or any successor of such
          Institute (or if such organization or successor shall no longer be in
          existence, a recognized national association or institute of land
          appraisers). Failure on the part of the Tenant to make a timely and
          proper demand for such appraisal shall constitute a waiver of the
          right thereto. Within ten (10) business days after the service of the
          demand for appraisal, Landlord shall give notice to Tenant, specifying
          the name and address of the person designated by Landlord to act as
          appraiser on its behalf who shall be similarly qualified. If Landlord
          fails to notify Tenant of the appointment of its appraiser, within or
          by the time above specified then the Tenant may thereafter send a
          second notice to Landlord indicating such failure and requesting
          Landlord to appoint such an appraiser. If Landlord fails to




                                      -57-

<PAGE>




          notify Tenant of the appointment of its appraiser within ten (10)
          business days after the giving of such second notice by Tenant then
          the appraiser appointed by Tenant shall be the sole appraiser to
          determine the issue.

      (b) In the event that two (2) appraisers are chosen pursuant to Section
          7.01(a) above, the appraisers so chosen shall meet within ten (10)
          business days after the second appraiser is appointed and, if within
          ten (10) business days after such first meeting the two appraisers
          shall be unable to agree upon a determination of Fair Market Net Rent,
          they, themselves, shall appoint a third appraiser, who shall be a
          competent and impartial person with qualifications similar to those
          required of the first two appraisers. In the event they are unable to
          agree upon such appointment within five (5) business days after
          expiration of said ten (10) day period, the third appraiser shall be
          selected by the parties themselves, if they can agree thereon, within
          a further period of ten (10) business days. If the parties do not so
          agree, then either party, on behalf of both, may request appointment
          of such a qualified person by an officer of the American Arbitration
          Association in Boston. The three (3) appraisers shall decide the
          dispute, if it has not previously been resolved, by following the
          procedure set forth in Section 7.01(c) below.

      (c) Where the issue cannot be resolved by agreement between the two
          appraisers selected by Landlord and Tenant or settlement between the
          parties during the course of the appraisal process, the issue shall be
          resolved by the three appraisers in accordance with the following
          procedure. The appraiser selected by each of the parties shall each
          state in writing his determination of the Fair Market Net Rent,
          supported by the reasons therefor, with counterpart copies to each
          party. The appraisers shall arrange for a simultaneous exchange of
          such proposed determinations. The role of the third appraiser shall be
          to select which of the two proposed determinations most closely
          approximates his own determination of Fair Market Net Rent. The third
          appraiser shall have no right to propose a middle ground or any
          modification of either of the two proposed determinations. The
          determination he chooses as most closely approximating his
          determination shall constitute the decision of the appraisers and be
          final and binding upon the parties. This provision for determination
          by appraisal shall be specifically enforceable to the


                                      -58-

<PAGE>




          extent such remedies are available under applicable law, and any
          determination hereunder shall be final and binding upon the parties
          hereto, and either party shall have the right to enter judgement
          thereon, unless otherwise provided by applicable law. If a
          determination of Fair Market Net Rent is to be made pursuant to this
          Section 7.01, Landlord and Tenant shall each pay for the fees and
          disbursements of any appraiser appointed by it and shall share equally
          in the fees and expenses of any third appraiser.

      (d) In the event of a failure, refusal or inability of any appraiser to
          act, his successor shall be appointed by him, but in the case of the
          third appraiser, his successor shall be appointed in the same manner
          as provided for appointment of the third appraiser.

                                    ARTICLE 8

                                  MISCELLANEOUS
                                  -------------

8.01. Holding Over. In the event of holding over by Tenant after expiration or
termination of this Lease without the written consent of Landlord, Tenant shall
pay for each month or portion thereof of the holdover tenancy holdover rent at
the rate of twice the rate of Gross Rent which Tenant was obligated to pay for
the month or portion thereof immediately preceding the end of the Term together
with such other amounts as may become due hereunder. No holding over by Tenant
after the Term or Extended Term shall operate to extend the Term. In the event
of any unauthorized holding over, Landlord may give notice to Tenant of such
holdover, and, if Landlord gives such notice to Tenant, Tenant shall indemnify
Landlord (i) against all claims for damages by any other tenant to whom Landlord
may have leased all or any part of the Leased Premises covered hereby effective
upon the termination of this Lease, and (ii) for all other losses, costs and
expenses, including reasonable attorneys' fees, incurred by Landlord by reason
of such holding over. Landlord shall include in its notice to Tenant hereunder
an estimate of the damages which Landlord reasonably anticipates suffering in
the six (6) months following such notice as a result of Tenant's holdover, but
such indemnity shall be effective whether or not any of the damages actually
suffered by Landlord were set forth in Landlord's notice to Tenant and shall not
in any manner be limited to Landlord's failure to list any such damage in its
notice to Tenant so long as Landlord





                                      -59-

<PAGE>




was reasonable in furnishing Tenant its estimate. Any holding over with the
consent of Landlord in writing shall thereafter constitute a lease from month to
month subject to the terms hereof.

8.02. Amendments and Modifications. This Lease may not be altered, changed or
amended, except by an instrument in writing signed by both parties hereto. If in
connection with obtaining financing for the Building, a bank, insurance company,
pension trust or other institutional lender shall request modifications to this
Lease as a condition to such financing, Tenant shall promptly consider such
requests, shall give serious consideration to all reasonable requests, and, if
Tenant shall not consent to any such request, shall set forth in writing the
reasons for its refusal to do so. No modification which would increase the
obligations of Tenant hereunder or materially adversely affect the leasehold
interest hereby created shall be deemed a reasonable request.

8.03. Transfers by Landlord. Landlord shall have the right to transfer and
assign all of its rights and obligations hereunder in the Building, and in such
event and upon such transfer, no further liability or obligations shall
thereafter accrue for obligations arising after such transfer or assignment
against such party as Landlord hereunder. No owner of the Leased Premises shall
be liable under this Lease except for breaches of Landlord's obligations
occurring while such person is the owner of the Leased Premises.

8.04. Severability. If any term or provision of this Lease, or the application
thereof to any person or circumstances, shall to any extent be invalid or
unenforceable, the remainder of this lease, or the application of such provision
to persons or circumstances other than those as to which it is invalid or
unenforceable, shall not be affected thereby, and each provision of this Lease
shall be valid and shall be enforceable to the fullest extent permitted by law.

8.05. Notices. All notices, demands, consents and approvals which may be or are
required to be given by either party to the other hereunder shall be in writing
and shall be deemed to have been fully given (a) in the case of Landlord, when
personally delivered to the Landlord at the address specified for Landlord on
the Basic Lease Information Sheet, and in the case of Tenant, when two (2) of
the same are personally delivered to the Tenant addressed "Attention: General
Counsel" and to the Tenant addressed "Attention: Treasurer", both at the address
specified for Tenant on the Basic Lease Information Sheet (provided, however,
that in the case of any notice by Landlord to Tenant regarding a lien pursuant
to Section 4.06 or regarding an Event of


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<PAGE>




Default pursuant to Section 6.01, such notice shall state "NOTICE OF LIEN" or
"NOTICE OF DEFAULT", respectively, in boldfaced capital letters), or (b) when
deposited with the United States mail, certified or registered, postage prepaid,
or with a recognized overnight delivery service which furnishes receipts of
delivery in the ordinary course of its business, in the case of Landlord, at the
address specified for Landlord on the Basic Lease Information Sheet, and in the
case of Tenant, addressed "Attention: General Counsel" and "Attention:
Treasurer", both at the address specified for Tenant on the Basic Lease
Information Sheet (provided, however, that in the case of any notice by Landlord
to Tenant regarding a lien pursuant to Section 4.06 or regarding an Event of
Default pursuant to Section 6.01, such notice shall state "NOTICE OF LIEN" or
"NOTICE OF DEFAULT", respectively, in boldfaced capital letters). Any party may,
from time to time, designate a new address for delivery, for purposes of this
notice provision, by notice given at least fifteen (15) days in advance in
accordance herewith of such new address.

8.06. No Joint Venture. This Lease shall not be deemed or construed to create or
establish any relationship of partnership or joint venture or similar
relationship or arrangement between Landlord and Tenant hereunder.

8.07. Successors and Assigns. This Lease shall be binding upon and inure to the
benefit of Landlord, its successors and assigns (subject to the provisions
hereof, including, but without limitation, Section 8.03); and shall be binding
upon and, subject to the provisions of Section 4.06 hereof, inure to the benefit
of Tenant, its successors and assigns.

8.08. Applicable Law. All rights and remedies of Landlord and Tenant under this
Lease shall be construed and enforced according to the laws of the Commonwealth
of Massachusetts.

8.09. Time of the Essence. Time is of the essence of each and every covenant
herein contained.

8.10. Submission Not an Option. The submission of this Lease for examination
does not constitute a reservation of or option for the Leased Premises or an
offer to lease, it being understood and agreed that neither Landlord nor Tenant
shall be legally bound with respect to the leasing of the Leased Premises unless
and until this Lease has been executed and delivered by both Landlord and
Tenant.

8.11. Brokerage. Tenant and Landlord each warrant to the other that it has had
no dealings with any broker or agent in connection with this Lease other than
Meredith & Grew and Leggat McCall/Grubb



                                      -61-

<PAGE>




and Ellis Inc., and each covenants to defend (with counsel reasonably approved
by the other party), hold harmless and indemnify the other party from and
against any and all costs, expense or liability for any compensation, commission
and charges claimed by any broker or agent arising out of the warranting party's
dealings in connection with this Lease or the negotiation thereof. The fee for
the brokers referred to above shall be paid by Landlord.

8.12. Waiver of Jury Trial. Landlord and Tenant hereby waive trial by jury in
any action, proceeding or counterclaim brought by either of the parties hereto
against the other, on or in respect of any matter whatsoever arising out of or
in any way connected with this Lease, the relationship of Landlord and Tenant
hereunder, Tenant's use or occupancy of the Leased Premises, and/ or any claim
of injury or damages.

8.13. All Agreements Contained. This Lease contains all of the agreements of the
parties with respect to the subject matter hereof and supersedes all prior
dealings between them with respect to such subject matter.

8.14. Cumulative Remedies. The specific remedies to which Landlord may resort
under the terms of this Lease are cumulative and are not intended to be
exclusive of any other remedies or means of redress to which it may be lawfully
entitled in case of any breach or threatened breach by Tenant of any provisions
of this Lease. In addition to the other remedies provided in this Lease,
Landlord and Tenant shall each be entitled to the restraint by injunction of the
violation or attempted or threatened violation of any of the covenants,
conditions or provisions of this Lease or to a decree compelling specific
performance of any such covenants, conditions or provisions.

8.15. Failure to Enforce. The failure of Landlord or Tenant to declare any
default upon its occurrence or to seek redress for any default of, or to insist
upon strict performance of, any covenant or condition of this Lease, shall not
be deemed a waiver of such default, nor prevent a subsequent act which would
have originally constituted a default from having all the force and effect of
the original default. The failure of the Landlord to enforce any of the rules
and regulations applicable to the Building against any other tenant in the
Building shall not be deemed a waiver of any such rules or regulations,
provided, however, that Landlord shall not enforce such rules and regulations in
a discriminatory manner. The receipt by Landlord of Rent with knowledge of the
breach of any covenant of this Lease shall not be deemed a waiver of such
breach. No provision of this Lease shall be deemed to have been waived by
Landlord, unless such waiver shall be in writing and


                                      -62-

<PAGE>




signed by Landlord. No consent or waiver, express or implied, by Landlord or
Tenant to any breach of any agreement or duty shall be construed as a waiver or
consent to or of any other breach of the same or any other agreement or duty.

8.16. Notice of Lease; Other Notices and Agreements. Tenant agrees not to record
this Lease, but on the request of either party hereto, both parties hereto shall
execute and deliver (i) a notice of this Lease in form appropriate for recording
and registration, (ii) an agreement setting forth the Term Commencement Date,
(iii) a notice in form appropriate for recording and registration of any
amendment of this Lease, (iv) as reasonably requested by any holder of a
Mortgage, an agreement by Tenant to make payments and give notices to whatever
individual or entity shall be designated by Landlord for receiving any such
notice or payment and to comply with the provisions of any assignment of rents
granted to the holder of any Mortgage, and (v) if this Lease is terminated
before the expiration of the Term, an instrument in form appropriate for
recording and registration pursuant to which Tenant acknowledges the date of
termination.

8.17. Moving Expense Reimbursement. Landlord agrees to reimburse Tenant for
expenses incurred by Tenant in relocating to the Leased Premises in an amount
equal to One Dollar ($1.00) per square foot of Net Rentable Area of the Leased
Premises at the time of Tenant's initial occupancy. Such amount shall be payable
by Landlord to Tenant in cash installments as such expenses are incurred by
Tenant in the ordinary course of such relocation in a manner consistent with
normal business practices during the second year of the Term, with each
installment due within thirty (30) days of Landlord's receipt of an invoice
therefor from Tenant. Tenant agrees not to voluntarily prepay any of such moving
expenses.

8.18. Release of Existing Lease Obligations. Tenant is expected to have
continuing obligations under Tenant's existing leases at One Memorial Drive,
Cambridge or One Beacon Street, Boston (the "Existing Leases") with respect to
the period from the Completion Date to the Rent Commencement Date. Any cost
savings achieved by subletting or assigning any portion of the premises under
the Existing Leases, successfully negotiating a release of Tenant from any of
Tenant's obligations to pay rent or escalations under the Existing Leases, or
reducing any identifiable operating costs payable to the landlord under the
Existing Leases or to a utility company providing service to the premises
demised under the Existing Leases (as determined in comparison to the such costs
for the full calendar year immediately preceding the Completion Date), shall be
shared equally by Landlord and Tenant, after deducting any cost incurred by
Tenant which is associated with achieving the



                                      -63-

<PAGE>




same. Nothing stated herein shall obligate Tenant to achieve any such savings,
but Tenant shall discuss with Landlord in good faith any attempts at achieving
such savings and pursue in good faith such efforts as Tenant shall determine is
appropriate to achieve such savings (it being understood that Tenant may, in
good faith, elect not to relocate all or any portion of its operations for the
first year after the Term Commencement Date).

8.19. Hiring Practices. Tenant covenants that Tenant shall comply with all laws,
ordinances, regulations and orders referenced in Section 12.01 of the Amended
and Restated Sale and Construction Agreement by and among the City of Boston,
the Boston Redevelopment Authority, New England Mutual Life Insurance Company
and Gerald D. Hines Interests, Inc. dated April 15, 1986, recorded with the
Suffolk Registry of Deeds in Book 12515, Page 78. Notwithstanding any other
provision of this Lease, Landlord shall have no right to terminate this Lease by
reason of Tenant's breach of this covenant, but Tenant shall in good faith make
reasonable efforts to cure any breach of this covenant after notice to Tenant
from any public agency, authority or other instrumentality with Jurisdiction to
enforce any such laws, ordinances, regulations or orders that Tenant has failed
to so comply, or after notice to Tenant from Landlord that Landlord has received
notice from any such public agency, authority or other instrumentality that
Tenant has failed to so comply, provided that Tenant may in good faith challenge
any assertion by a public agency, authority or other instrumentality that Tenant
has failed to so comply or the validity or enforceability of any such laws,
ordinances, regulations or orders.


                                    ARTICLE 9

                           OPTIONS TO EXTEND THE TERM
                           --------------------------


9.01. Grant and Exercise of Options to Extend. So long as there shall exist, at
the time of the giving of Tenant's Two Year Notice or Tenant's Five Year Notice
hereunder, as the case may be, no Event of Default, or condition as to which
Tenant has received notice, which, with the passage of time, would constitute an
Event of Default (unless Tenant commences to cure such condition prior to the
occurrence of an Event of Default as a result thereof and thereafter
continuously and diligently pursues such cure to completion), Tenant shall have
the right to extend the Term beyond the Term Expiration Date (such extension
being hereinafter referred to as an "Extended Term") for either (i) one
additional two (2) year period by giving Landlord notice of its election to
extend ("Tenant's Two Year Notice") no less than thirty-six (36)



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<PAGE>




months prior to the Term Expiration Date (the "Two Year Option") or (ii) one
additional period of five (5) years by giving Landlord notice of its election to
extend ("Tenant's Five Year Notice") no less than twenty-four (24) months prior
to the Term Expiration Date (the "Five Year Option"). The giving of Tenant's Two
Year Notice or Tenant's Five Year Notice by Tenant, as the case may be, shall
automatically extend the term of the Lease for the applicable Extended Term. In
the event Tenant elects to exercise the Five Year Option, and so long as there
shall exist, at the time of the giving of Tenant's Second Notice hereunder, no
Event of Default, or condition as to which Tenant has received notice, which,
with the passage of time, would constitute an Event of Default (unless Tenant
commences to cure such condition prior to the occurrence of an Event of Default
as a result thereof and thereafter continuously and diligently pursues such cure
to completion), Tenant shall also have the right to an additional Extended Term
(the "Additional Extended Term") for one additional period of five (5) years or
ten (10) years (as determined by Landlord in its sole discretion) (the "Extra
Option"). In the event Tenant desires to exercise the Extra Option, Tenant
shall, no earlier than thirty-six (36) months prior to the end of the existing
Extended Term and no later than twenty-six (26) months prior to the end of the
existing Extended Term, provide Landlord notice of such intention and request
Landlord to determine whether the length of the Additional Extended Term shall
be five (5) years or ten (10) years ("Tenant's Notice of Intention"). Landlord
shall, within thirty (30) days of Tenant's Notice of Intention, notify Tenant
whether the length of the Additional Extended Term stall be five (5) years or
ten (10) years. Following such determination by Landlord, Tenant may exercise
the Extra Option by giving Landlord notice of such election ("Tenant's Second
Notice") no later than twenty-four (24) months prior to the end of the existing
Extended Term. The giving of Tenant's Second Notice by Tenant shall
automatically extend the term of the Lease for the Additional Extended Term.
Failure by Tenant to give any notice required hereunder in a timely manner shall
constitute a waiver of such Option to Extend and any subsequent Option to
Extend. If Tenant does not exercise either the Two Year Option or the Five Year
Option, the Term shall continue until the Term Expiration Date; if the Tenant
exercises the Five Year Option, but fails to exercise the Extra Option, the Term
shall continue until the last day of the first Extended Term.

9.02. Election to Reduce the Leased Premises. The rights to extend shall apply
only to all of the space included as a part of the Leased Premises on the last
day of the Term Expiration Date, or if Tenant exercises the Extra Option, on the
last day of the existing Extended Term; provided, however, that (a) Tenant may
elect in Tenant's Five Year Notice (but not in Tenant's Two Year



                                      -65-

<PAGE>




Notice) to reduce the Leased Premises for the Extended Term by eliminating from
the Leased Premises the top floor or the top two floors then included in the
Leased Premises, specified in such notice; and (b) Tenant may elect in Tenant's
Second Notice to reduce the Leased Premises for the Additional Extended Term by
eliminating from the Leased Premises the top floor then included in the Leased
Premises, as specified in Tenant's Second Notice, but only if Tenant did not
elect to reduce the Leased Premises in Tenant's Five Year Notice or elected to
reduce the Leased Premises by only one floor, or Tenant may elect to reduce the
Leased Premises for the Additional Extended Term by eliminating from the Leased
Premises the top two floors then included in the Leased Premises, but only if
Tenant did not elect to reduce the Leased Premises at all in Tenant's Five Year
Notice. If Tenant exercises its election to reduce the Leased Premises
hereunder, Tenant and Landlord shall execute an amendment to this Lease
appropriately revising the Basic Lease Information Sheet: (i) to delete the
floor or floors removed from the Leased Premises and deleting the floor or
floors from Exhibit A, (ii) to restate the Net Rentable Area of the Leased
Premises, and (iii) to restate the Tenant's Proportionate Share.

9.03. Rent During Extended Term. The Base Rent for the Extended Term shall be
(i) for the two year Extended Term, $16.00 plus seventy-five (75%) of the amount
by which Fair Market Net Rent exceeds $16.00 but in no event shall it be less
than $16.00 or (ii) for any other Extended Term, Fair Market Net Rent. Such Base
Rent shall be in effect as of the first day of such Extended Term. The Fair
Market Net Rent shall be determined by Landlord with notice given to Tenant no
later than one hundred and twenty (120) days prior to the commencement of the
Extended Term subject to the Tenant's right to demand appraisal pursuant to the
provisions of Section 7.01. Failure on the part of the Landlord to give such
notice in a timely manner shall not vitiate the right to require an adjustment
of the Base Rent but such delay shall result in deferral of any increase or
decrease in the Base Rent to a date one hundred and twenty (120) days after the
date of such notice. Failure on the part of Tenant to demand appraisal within
thirty (30) days after receipt of notice from Landlord of Landlord's
determination of Fair Market Net Rent shall constitute a waiver of Tenant's
right to demand appraisal, and shall bind Tenant to the Fair Market Net Rent as
determined by Landlord. Should Tenant elect to exercise its right to demand
appraisal and should the appraisal process not have been concluded prior to the
Extended Term, then the greater of (i) the Base Rent which was previously in
effect or (ii) Tenant's estimate, if any, of the Fair Market Net Rent, as
applicable, shall be temporarily applicable for purposes of determining Tenant's
obligation to pay the Base Rent. However, once the new rate is in fact agreed
upon or determined,



                                      -66-

<PAGE>




if it is higher than the rate paid by Tenant during the period such rate should
have been in effect, then Tenant shall pay to Landlord within ten (10) days
after agreement upon or determination of the new rate an amount sufficient to
result in Landlord's having been paid rental at the new rate from the
commencement of the portion of the term during which such rate was to have been
in effect, together with interest at the then Bank of Boston Prime Rate with
respect to any portion of such rent not paid when due because of the operation
of this paragraph, from the date payment was due to the date paid.

9.04. Lease Continues in Effect. From and after commencement of each Extended
Term hereunder, all of the other terms, covenants and conditions of this Lease
shall apply, and reference to the Term shall thereafter be deemed to include the
Extended Term in question, except that the Base Rent shall be revised by an
amendment to the Lease to reflect any adjustment in the Base Rent, and from and
after the commencement of the two year Extended Term or the Additional Extended
Term, as the case may be, Tenant shall have no right to extend the Term further.


                                   ARTICLE 10

                      OPTIONS TO EXPAND THE LEASED PREMISES
                      -------------------------------------

10.01. Grant of Initial Option to Expand. Tenant may elect to Increase the
Leased Premises by leasing between 5,000 and 8,000 square feet of space on the
second or twelfth floor of the Building (the specific amount and location of
such space to be determined by Landlord at the time of Tenant's notice of its
intention to exercise such option) by providing notice to Landlord on or before
December 31, 1991. If Tenant exercises its option hereunder, Tenant and
Landlord shall execute an amendment to this Lease appropriately revising the
Basic Lease Information Sheet: (i) to identify the space added to the Leased
Premises and adding the space to Exhibit A. (ii) to restate the Net Rentable
Area of the Leased Premises, and (iii) to restate the Tenant's Proportionate
Share. All other terms, covenants and conditions of the Lease shall remain
unchanged and in full force and effect.

10.02. Grant of Options to Expand.

     (a)  Provided that (i) no Event of Default, or condition as to which Tenant
          has received notice, which, with the passage of time would constitute
          an Event of Default, (unless Tenant commences to cure such condition
          prior to the occurrence of an Event of Default as a result



                                      -67-

<PAGE>




          thereof and diligently pursues such cure to completion), then exists,
          and (ii) Tenant and/or any Tenant Affiliates, shall then be in
          occupancy of Net Rentable Area constituting not less than seventy-five
          percent (75%) of the Net Rentable Area included in the Leased Premises
          on the date of Tenant's Expansion Notice, Tenant shall have the option
          to expand the Leased Premises at the times set forth below, subject to
          the other provisions set forth below, by adding the following space
          located on floors eleven (11) through twenty-two (22) of the Building,
          as determined by Landlord pursuant to this Section 10.02
          (collectively, the "Expansion Space"):

          (1) One entire floor located on floors eleven (11) through twenty-two
              (22) to be made available between September 1995 and September
              1997;

          (2) One entire floor located on floors eleven (11) through twenty-two
              (22) to be made available between September 1997 and September
              1999;

          (3) One entire floor located on floors eleven (11) through twenty-two
              (22) to be made available between July 2000 and July 2002.

      (b) If Landlord shall be unable to deliver any portion of the Expansion
          Space at the time required hereunder, by reason of the holding over of
          any prior tenant or occupant or otherwise due to no fault of Tenant,
          Landlord shall use reasonable efforts to obtain possession of such
          Expansion Space and otherwise deliver possession thereof to Tenant,
          but Landlord shall not be subject to any liability for failure to give
          possession thereof to Tenant at the time required hereunder, except
          that (i) until the date on which all such Expansion Space shall
          actually be delivered to Tenant, Tenant shall not be required to pay
          to Landlord any Rent with respect to the Net Rentable Area of such
          Expansion Space, unless and to the extent Tenant has commenced
          occupancy of such portion of the Expansion Space for the conduct of
          its business operations, (ii) if Landlord shall be unable to deliver
          all of such Expansion Space within six (6) months after the time
          required hereunder, Tenant shall have the option to terminate its
          election to take such Expansion Space (or, if Landlord has delivered
          only a portion of such Expansion Space, the remainder of such
          Expansion Space) by notice to Landlord given within fifteen (15) days
          thereafter, and (iii) if



                                      -68-

<PAGE>




          Landlord shall be unable to deliver all of such Expansion Space within
          twelve (12) months after the time required hereunder, Tenant shall
          have the option to terminate its election to take such Expansion Space
          (or, if Landlord has delivered only a portion of such Expansion Space,
          the remainder of such Expansion Space) by notice to Landlord given
          within fifteen (15) days thereafter. In addition to the foregoing, if,
          as part of Tenant's Expansion Notice (as defined in Section 10.03(a)),
          Tenant shall notify Landlord that such Expansion Space is to be
          utilized in conjunction with existing space in the Leased Premises for
          the operation of a single division or other business unit of Tenant,
          and if Landlord shall be unable to deliver the Expansion Space under
          clause (iii) above, then Tenant may elect in its notice to terminate
          its election to take such Expansion Space to reduce the Leased
          Premises by eliminating from the Leased Premises the top floor then
          included in the Leased Premises. If Tenant exercises its election to
          reduce the Leased Premises hereunder, Tenant and Landlord shall
          execute an amendment to this Lease appropriately revising the Basic
          Lease Information Sheet: (i) to delete the floor removed from the
          Lease Premises and deleting the floor or floors from Exhibit A, (ii)
          to restate the Net Rentable Area of the Leased Premises, and (iii) to
          restate the Tenant's Proportionate Share.

      (c) Landlord shall use reasonable efforts to keep Tenant informed of the
          status, from time to time, of the space which may constitute Expansion
          Space hereunder.

10.03. Exercise of Options to Expand.

      (a) Landlord shall furnish Tenant not less than fifteen (15) months nor
          more than twenty-four (24) months prior notice of the time when such
          Expansion Space is scheduled to become available within the time
          periods set forth in Section 10.02(a) hereof. Such notice shall set
          forth the floor of the Building constituting such space, the date on
          which Landlord estimates that the Expansion Space will become
          available, and the Landlord's determination of Fair Market Net Rent.
          Tenant may thereupon exercise its option to add Expansion Space to the
          Leased Premises by giving notice ("Tenant's Expansion Notice") to
          Landlord not later than twelve (12) months prior to the date on which
          such





                                      -69-

<PAGE>




          Expansion Space is scheduled to become available. Tenant's exercise of
          its options shall be final and shall not depend upon the determination
          of Fair Market Rent pursuant to Article 7.

      (b) Tenant's failure to give Landlord timely notice of the exercise of its
          option to expand shall constitute a final waiver of its option to take
          Expansion Space during the applicable time period set forth in Section
          10.02(a) hereof, and Landlord shall have no further obligation to make
          such Expansion Space available to Tenant except during the next time
          period set forth in Section 10.02(a) hereof, if any.

      (c) In the event that any of the Expansion Space becomes available before
          the time indicated in Section 10.02(a) for such space, Landlord shall
          so notify Tenant, and Tenant shall thereupon have the right to
          accelerate its corresponding option to expand with respect to such
          Expansion Space, by notice to Landlord not later than thirty (30) days
          after the date of Landlord's notice of availability. Such notice by
          Tenant shall, for all purposes, be deemed to be the Tenant's Expansion
          Notice required by Section 10.03(a). Tenant's exercise of such option
          to expand shall constitute the option to expand which would have
          occurred during the next time period set forth in Section 10.02(a),
          and Tenant shall not thereafter have any additional option to expand
          during such time period, but Tenant's failure to exercise such option
          to expand shall not negate Tenant's option to expand during such time
          period.

10.04. Rent for Expansion Space. Tenant shall pay to Landlord all of the Rent
required hereunder with respect to the Expansion Space; provided, however, that
the Base Rent shall be adjusted to reflect the then Fair Market Net Rent for the
Expansion Space, such Fair Market Net Rent to be determined by Landlord, subject
to Tenant's right to demand appraisal in accordance with the provisions of
Article 7. Notwithstanding anything in this Lease to the contrary, it is agreed
that for the purposes of this Section 10.04, neither the value of any demolition
work performed by Landlord pursuant to Section 10.05(b), nor the value of the
sixty (60) day period referred to in this Section 10.04 shall be considered in
calculating the Fair Market Net Rent. Payment of Rent with respect to Expansion
Space shall commence on the earlier of (i) occupancy by Tenant for the conduct
of its business or (ii) sixty (60) days after Landlord makes the Expansion Space
available to Tenant in the condition required by Section 10.05 hereof.



                                      -70-

<PAGE>




10.05. Condition of Expansion Space. All Expansion Space shall be leased by and
delivered to Tenant on an "as is" basis, except as follows:

      (a) If any portion of the Expansion Space is unimproved at the time of the
          exercise of Tenant's option to expand, Landlord shall provide Building
          Standard Improvements in accordance with Schedule I of the Work
          Letter, prior to the Expansion Space being made available to Tenant.

      (b) If the Expansion Space has been previously constructed, Landlord will
          repair all floor cuts and will demolish walls, doors, millwork and
          other items in the occupiable space in accordance with plans and
          written instructions prepared by Tenant and delivered to Landlord no
          later than ninety (90) days prior to the date on which Landlord
          estimates the Expansion Space will become available as set forth in
          Landlord's notice to Tenant in accordance with Section 10.03(a)
          hereof, prior to the Expansion Space being made available to Tenant.

10.06. Expansion Space Part of Leased Premises. Upon Tenant's exercise of each
option to expand, the particular Expansion Space shall become a part of the
Leased Premises on the date Landlord makes the Expansion Space available to
Tenant in the condition required by Section 10.05 hereof, and thereafter the
Expansion Space shall be subject to all of the terms, covenants and conditions
of this Lease, as the same may be amended from time to time, except that Rent
shall not commence with respect to the Net Rentable Area of the Expansion Space
until the earlier of (a) occupancy by Tenant for the conduct of its business, or
(b) sixty (60) days after the date the Expansion Space became part of the
Premises. Tenant and Landlord shall execute an amendment to this Lease
appropriately revising the Lease to reflect the addition of such Expansion
Space, including the Basic Lease Information Sheet: (i) to identify the floor or
portion thereof added to the Leased Premises and adding the same to Exhibit A,
(ii) to restate the Net Rentable Area of the Leased Premises, (iii) to restate
the Tenant's Proportionate Share, and (iv) to add the Base Rent to be paid by
Tenant with respect to the Expansion Space.








                                      -71-

<PAGE>




                                   ARTICLE 11

                              FIRST RIGHT TO LEASE
                              ---------------------

11.01. Exercise of First Right to Lease. Provided that no Event of Default, or
condition as to which Tenant has received notice which, with the passage of time
would constitute an Event of Default (unless Tenant commences to cure such
condition prior to the occurrence of an Event of Default as a result thereof and
thereafter continuously and diligently pursues such cure to completion) then
exists and that Tenant and/or any Tenant Affiliates occupy not less than
seventy-five percent (75%) of the Net Rentable Area included in the Leased
Premises on the date of Tenant's First Lease Notice, and not greater than
eighty-five percent (85%) of the total Net Rentable Area of the Office Section
of the Building, Landlord shall offer any space that becomes Available Space on
floor(s) eleven (11) through twenty-two (22) to Tenant for such rent and upon
such other terms as Landlord proposes to offer such Available Space to third
parties and otherwise substantially upon the terms and conditions set forth
herein. In addition to any obligation of Landlord to inform Tenant of Available
Space set forth below, Landlord agrees to use reasonable efforts to periodically
advise Tenant of space in the Building which is scheduled to become Available
Space. Tenant's first right to lease shall be exercised as follows:

      (a) Not later than sixty (60) days prior to the expiration of the term
          then applicable to such Available Space (except in cases where the
          term expires by reason of default or other causes which cannot
          reasonably be foreseen by Landlord, in which case Landlord shall give
          reasonable notice), Landlord shall give notice to Tenant of the
          expected availability of such Available Space together with a summary
          of the financial terms and other key provisions (to the extent
          different from the terms of this Lease) on which Landlord proposes to
          offer such Available Space to third parties for lease.

      (b) At any time within fifteen (15) days after Landlord gives the notice
          described in subsection (a), Tenant may, by notice to Landlord
          ("Tenant's First Lease Notice"), elect to (i) lease the Available
          Space described in Landlord's summary for the consideration and upon
          the business terms set forth in Landlord's summary, or (ii) lease the
          Available Space described in Landlord's summary for Fair Market Net
          Rent and upon



                                      -72-

<PAGE>




          such other of the business terms set forth in Landlord's summary as
          are consistent therewith, such Fair Market Net Rent to be as agreed
          upon by Landlord and Tenant within thirty (30) days of Tenant's First
          Lease Notice or, if the parties cannot agree, as determined in
          accordance with Article 7, or (iii) waive its first right to lease
          with respect to such Available Space. Tenant's failure to elect by
          notice to Landlord one of the options set forth above within said
          fifteen (15) days shall be deemed an election to waive the first right
          to lease such Available Space.

      (c) In the event Tenant elects to lease such Available Space, Landlord and
          Tenant shall promptly (but not later than forty-five (45) days prior
          to the expiration of the term then applicable to such Available Space)
          enter into an amendment to this Lease adding the Available Space to
          the Leased Premises for the consideration and upon the terms set forth
          in Landlord's summary (subject to Tenant's right to demand appraisal
          if option (ii) set forth in (b) above is elected), or, at Landlord's
          election, a new lease for the Available Space for the consideration
          and upon the terms set forth in Landlord's summary and such other
          terms and conditions as are contained in this Lease, or as Landlord
          and Tenant may mutually agree (subject to Tenant's right to demand
          appraisal if option (ii) set forth in (b) above is elected).

      (d) In the event Tenant elects or is deemed to elect to waive its right to
          lease such Available Space, Landlord shall be free to lease the
          Available Space to any other party; provided, however, that if
          Landlord has not entered into a lease or commitment to lease the
          Available Space within six (6) months after Landlord's notice to
          Tenant of the availability of the Available Space, Landlord shall
          reoffer the Available Space to Tenant by notice to Tenant given within
          such six (6) month period accompanied by a summary of the financial
          terms and other key provisions (to the extent different from the
          summary provided in the previous notice) on which Landlord proposes to
          offer to lease the Available Space to third parties. Tenant's first
          right to lease shall be a continuing right and Landlord shall continue
          to provide such a notice within each subsequent six (6) month period
          until Landlord has entered into a lease or commitment to lease such
          Available Space.





                                      -73-

<PAGE>




                                   ARTICLE 12

                               ADDITIONAL OPTIONS
                               ------------------

12.01. Parking. Tenant shall have the right to park in the Parking Section a
total of up to fifty (50) automobiles, the precise number to be designated by
Tenant by notice to Landlord not later than December 31, 1991. Landlord agrees
to designate, by a sign or other reasonable means determined by Landlord, one of
the spaces in the Parking Section as a space for the exclusive use of Tenant,
but Landlord shall have no obligation to ensure compliance by third parties with
such designation or the availability of such space for use by Tenant. Landlord
agrees that if in excess of ten percent (10%) of the parking spaces in the
Parking Section become designated for particular tenants, Tenant shall be
entitled to the identical percentage of the parking spaces allocable to Tenant
similarly designated. If Tenant does not require all of the parking spaces
allocable to it, Tenant shall relinquish its right to such parking spaces to
Landlord, whereupon Tenant shall no longer have a right to such relinquished
parking spaces and shall obtain future additional parking solely on a
space-available basis; provided, however, that Tenant shall have the right to
two (2) additional parking spaces for each floor in the Building which it adds
to the Leased Premises after the Term Commencement Date or if greater, the
number of spaces which the immediately preceding tenant or tenants of such floor
had the right to use pursuant to leases with Landlord, provided Tenant notifies
Landlord no less than ninety (90) days prior to the date on which such floor is
scheduled to be added to the Leased Premises of the number of parking spaces, if
any, which Tenant requires. Landlord agrees to provide Tenant with information
regarding the availability of parking spaces upon the request of Tenant during
the Term of this Lease and shall within thirty (30) days of notice from Tenant
that it desires additional parking spaces and the number which it desires,
inform Tenant of whether such spaces are then available, or how many are
available, and the terms upon which such spaces are available. Tenant shall
execute a separate license agreement with the garage operator with respect to
the parking spaces allocable to the Tenant. The rates charged by the garage
operator for such parking shall be the prevailing market rates for parking in
the Building as established by the garage operator from time to time, which
shall not unreasonably exceed (as determined by Landlord in its reasonable
business judgment) the average parking rates in comparable first class office
buildings in Boston. Tenant's right to use the parking spaces shall be subject
to (i) compliance with





                                      -74-

<PAGE>




the license agreement between Tenant and the garage operator, (ii) such
reasonable rules and regulations as Landlord or its operator may establish for
the Building from time to time, and (iii) all applicable laws, ordinances and
regulations.

12.02. Storage Area. Tenant shall have the option to lease the Storage Area,
located on floor P3 of the Building, and more specifically described on Exhibit
C attached to the Lease, by notice given to Landlord prior to January 1, 1992.
If Tenant exercises such option, the Storage Area shall be used by Tenant upon
the following terms, covenants and conditions:

      (a) Tenant shall pay as part of Gross Rent an amount equal to Ten Dollars
          ($10.00) per square foot of Net Rentable Area of the Storage Area for
          each year of the Term. During any Extended Term, the Rent per square
          foot of Net Rentable Area of the Storage Area for each year shall be
          increased by multiplying Ten Dollars ($10.00) by a fraction, the
          numerator of which is the Base Rent payable during such Extended Term
          and the denominator of which is Twelve and 27/100 Dollars ($12.27).

      (b) There shall not be a separate Operating Cost or Impositions charge to
          Tenant with respect to the Storage Area; rather, the cost of
          maintaining, repairing and operating the Storage Area and Impositions
          thereon, shall be paid by Landlord as a part of the cost of operating
          and maintaining the Building, and shall be included in the total
          Operating Cost and Impositions allocated among the tenants in the
          Building.

      (c) Tenant shall be responsible for maintenance of the interior of the
          Storage Area and shall assume all risk of loss or damage with respect
          to property stored therein, except to the extent that such loss is
          caused by the negligence or willful misconduct of Landlord.
          Maintenance of the exterior of the Storage Area, the portion of the
          Building in which the Storage Area is located and access thereto shall
          be the responsibility of Landlord, which Landlord shall perform in the
          same manner as is provided with respect to other areas in the Building
          for which Landlord has retained responsibility.

      (d) Landlord shall deliver the Storage Area to Tenant hereunder on a
          "shell" basis, which shall consist of space enclosed by a concrete or
          sheet rock wall and a






                                      -75-

<PAGE>




          concrete floor, one lockable entry, lights provided by strip lighting
          and one light switch (or additional entries or light switches as may
          be required by the applicable building codes).

12.03. Antenna or Satellite Dish. Tenant shall have the right to install an
antenna, a satellite dish, or both, on the roof of the Building, subject to (i)
the availability of space for the installation of such antenna or satellite
dish, (ii) the obtaining of all permits and approvals from governmental
authorities required for such installation at Tenant's expense, and (iii) the
approval of Landlord after submission to Landlord of plans and specifications
therefor describing in sufficient detail the nature of the antenna or satellite
dish which Tenant wishes to install and the manner of its proposed installation,
which approval shall not be unreasonably withheld or delayed by Landlord. It
shall not be unreasonable for Landlord to withhold its consent to such
installation if Landlord determines that the installation of such antenna or
satellite dish would damage the aesthetic appearance of the Building from street
level or any public open space, interfere with sight lines from any portion of
the Project, or interfere in any manner with antennas, satellite dishes or other
structures then existing on the roof of the Building. The installation of any
such antenna and/or satellite dish shall be done at Tenant's sole cost and
expense, but, at the option of Landlord, the installation shall be effected by
Landlord at the reasonable cost and expense of Tenant. To the extent that the
installation will be undertaken directly by Tenant, the method of installation,
the materials to be used and the contractors to be performing the work shall be
subject to Landlord's approval, which approval shall not be unreasonably
withheld or delayed, and the installation shall be performed in accordance with
the provisions of Section 4.06 hereof. Tenant shall pay as a part of Gross Rent
an amount equal to the fair market rent, as determined by Landlord in its
reasonable business judgement, for the space utilized in connection with such
antenna or satellite dish for any period in which the same is maintained on the
roof of the Building.

12.04. Security. Tenant shall have the option to station one (1) security
officer/receptionist at the security desk located in the lobby of the Building.
Such security officer/receptionist shall not interfere with the security
officers retained by Landlord nor shall such security officer/receptionist
interfere with the use of the Building by Landlord, other tenants in the
building and their guests. Such security officer/receptionist shall also comply
with reasonable rules and requirements established by Landlord and Landlord's
security officers from time to time. At the reasonable request of Landlord,
Tenant shall replace any security officer/receptionist which it places in the
lobby of the Building with


                                      -76-

<PAGE>




another security officer/receptionist reasonably acceptable to Landlord.
Landlord agrees that any such request shall specify the nature of the problem
with the existing security officer/receptionist and specify the reason why
Landlord requests such security officer/receptionist be replaced. Landlord
agrees to take reasonable steps to cooperate with Tenant with respect to the
implementation of any security system installed by Tenant for the Leased
Premises, including, without limitation, a system which permits Tenant to use
the fire stairwells adjacent to the Leased Premises for interfloor access and
egress. The installation of any such system shall be subject to the provisions
of Section 4.06 hereof.

12.05 Exhibits. The Exhibits listed in the Schedule of Exhibits are incorporated
in this Lease by reference and are to be construed as part hereof.

                                   ARTICLE 13

                                   DEFINITIONS
                                   -----------

13.01. Definitions. Terms used herein shall have the following meanings:

"Additional Rent" shall mean all monetary obligations of Tenant hereunder, other
than the obligation for payment of Gross Rent.

"Available Space" shall mean space in the Office Section of the Building (i)
with respect to which a tenant's lease has terminated, whether by expiration or
earlier termination of the term of such lease, and which is not encumbered by
any extension option, right of first refusal or agreement of expansion, or
otherwise, and (ii) which has not been relet to such tenant immediately
thereafter, whether as a result of renewal, extension, a new lease or otherwise,
or with respect to which any expansion or like right previously granted to such
tenant or to a third person has not been exercised.

"Base Rent" shall mean the amount set forth on the Basic Lease Information
sheet, as adjusted in accordance with the provisions of the Lease.


"Basic Services" shall mean the services described in Section 3.01 hereof.







                                      -77-

<PAGE>




"Building" shall mean the 22-story building (consisting of a 6-story low-rise
portion, a 16 story high-rise portion and 3 levels of parking space below grade)
located on the Land, and comprising the Office Section, the Commercial Section,
the Parking Section together with the Common Areas.

"Building Common Areas" shall mean all areas of the Building servicing more than
one floor of the Building as a whole, including, but not limited to fire
stairwells, central mechanical rooms, elevator machine rooms, pump rooms,
loading dock facilities, electrical and communication rooms, postal, security
and janitorial facilities and the ground floor lobby (and if any such area is
bordered by any demising wall which abuts any space that is leasable, such area
shall be measured from the midpoint of such demising wall), but excluding Floor
Common Areas, General Common Areas and the Parking Section.

"Building Standard Improvements" shall mean the improvements specified in
Schedule II to the Work Letter.

"Business Hours" shall mean 8 A.M. to 6 P.M. on Business Days.

"Business Days" shall mean Monday through Friday excluding federal holidays.

"Commercial Section" shall mean that portion of the Building dedicated to
commercial and retail uses and not included in the Office Section.

"Common Areas" shall mean the Building Common Areas, the Floor Common Areas and
the General Common Areas.

"Completion Date" shall mean the later of (i) the Scheduled Completion Date or
(ii) the date on which the Leased Premises are Substantially Complete.

"Estimated Impositions" for any calendar year shall mean Landlord's estimate of
Impositions for such calendar year.

"Estimated Operating Cost" for any calendar year shall mean Landlord's estimate
of Operating Cost for such calendar year.

"Event of Default" shall have the meaning attributed to it in Section 6.01.

"Excess Building Standard Improvements" shall mean improvements of the type
specified in Schedule II to the Work Letter, in excess of the quantities set
forth in said Schedule II.




                                      -78-

<PAGE>



"Fair Market Net Rent" shall mean, subject to the last two sentences herein, the
annual rental value, net of Operating Cost and Impositions, of the space in
question, as determined by reference to comparable space being offered for rent
or recently rented in the Building or in comparable buildings in Boston,
Massachusetts, in each case taking into consideration the following factors
related to the Leased Premises: floor level, tenant improvements, proposed term
of lease, extent of service provided or to be provided, the lack of a brokerage
commission applicable to the transaction, the time the particular rate under
consideration became or is to become effective, the location of the Building,
the reputation of the Building, including its ownership and management, and any
other relevant terms or conditions (but specifically excluding the fact that
Tenant will not incur moving expenses). With respect to the determination of
Fair Market Net Rent for any Extended Term, all inducements which would
otherwise be offered excluding, however, the residual value of any Tenant
Alterations, Excess Building Standard Improvements or Premium Tenant
Improvements to the extent paid for by Tenant which are in the nature of capital
improvements rather than normal maintenance or repairs), giving due regard to
the factors cited above, shall be considered, but shall be factored into an
equation to arrive at a rental figure, net of such inducements, unless otherwise
agreed by Landlord and Tenant. With respect to the determination of Fair Market
Net Rent for any Expansion Space or Available Space, all inducements which would
otherwise be offered, giving due regard to the factors cited above, shall be
considered, and shall be included as part of a Fair Market Net Rent package for
such space, unless otherwise agreed by Landlord and Tenant.

"Floor Common Areas" shall mean all areas on those floors of the Building which
are from time to time occupied by more than one tenant which are devoted to
non-exclusive uses, such as corridors, lobbies, fire vestibules, elevator
foyers, service elevator receiving areas, mailrooms, electric and communication
closets and other similar facilities for the benefit of all tenants or invitees
on that particular floor, but excluding Building Common Areas, General Common
Areas and the Parking Section.

"Force Majeure" shall mean any circumstance beyond the reasonable control of
Landlord, including, without limitation, acts of God, acts of the public enemy,
governmental interference, court orders, requisition or orders of governmental
bodies or authorities, requirements under any statute, law, rule, regulation or
similar requirements of a governmental authority which shall be enacted or shall
arise following the date of this Lease, inability to obtain labor, insurrection,
riot, civil commotion, lock-out or any other





                                      -79-

<PAGE>




unforeseeable event (other than the inability to obtain financing), the
occurrence of which would prevent or preclude Landlord from fully and completely
carrying out and performing its obligations under this Lease.

"General Common Areas" shall mean those areas forming part of the Building and
devoted to non-exclusive uses which are not measured, including, but not limited
to, the "Winter Garden", walkways, courtyards and all landscaped areas
(including pools and fountains). General Common Areas shall not include Floor
Common Areas, Building Common Areas or the Parking Section.

"Gross Rent" shall mean, for each year of the Term, the sum of Base Rent,
Tenant's Proportionate Share of Operating Cost and Impositions, charges incurred
by Tenant for Extra Services in accordance with Section 3.02, and Rent for the
Storage Area, if any.


"Impositions" shall have the meaning attributed to it in Section 2.05.

"Initial Tenant Improvements" shall mean all initial improvements to be
constructed in the Leased Premises in accordance with the Work Letter.

"Initial Tenant Improvement Plans" shall mean the plans for the Initial Tenant
Improvements, as set forth in the Work Letter.

"Land" shall mean the parcel of real property owned by the Landlord, located in
the City of Boston, Suffolk County, Massachusetts, and bounded in part by
Berkeley and Boylston Streets and St. James Avenue and more specifically
described in Exhibit A-1 attached hereto.

"Landlord Responsible Parties" shall mean all agents, servants, employees,
contractors and business invitees of Landlord (but excluding other tenants of
the Project and their agents, servants, employees, contractors, licensees and
business invitees).

"Leased Premises" shall mean the floor area more particularly shown on Exhibit A
attached hereto, containing the Net Rentable Area specified on the Basic Lease
Information sheet.

"Loading Docks" shall mean the loading dock facilities serving the Project.

"Mortgage" shall mean any and all institutional mortgages securing indebtedness
for money borrowed by Landlord or indebtedness for the refinancing of any such
indebtedness, including all amendments



                                      -80-

<PAGE>




and modifications thereto, from time to time, provided any such mortgage
encumbers all or any portion of the Building, and provided further that with
respect to any Mortgage held by an affiliate of Landlord the indebtedness
secured thereby is actually debt financing for the Building (which may, however,
include an associated equity component), and the mortgage instrument reflects
terms consistent with an "arms length" transaction. Any reference to "Mortgage"
and "Mortgagee" herein shall include a sale and leaseback and the grantee-lessor
of a sale and leaseback used for financing purposes as limited hereby.

"Net Rentable Area" shall mean the area or areas of the space within the
Building determined as follows:

      (a) Net Rentable Area on a single tenancy floor in the Office Section
          shall consist of (i) the area determined by measuring from the inside
          surface of the outer glass of each exterior wall (and extensions of
          the plane thereof in non-glass areas) to the inside surface of the
          outer glass on the opposite exterior wall (and extensions of the plane
          thereof in non-glass areas), but shall exclude vertical penetrations
          (including, without limitation, fire stairs, elevator shafts, and
          areas for central heating, ventilation and air conditioning and
          mechanical and electrical facilities), as set forth on Exhibit E
          attached hereto for each corresponding floor; plus

          (ii) Tenant's Allocation of Building Common Areas, as set forth on
          Exhibit E attached hereto for each corresponding floor;

      (b) Net Rentable Area for a multi-tenancy floor shall consist of:

          (x) all space within the demising walls determined by measuring from
              the mid-point of the demising walls of each interior wall and from
              the inside surface of the outer glass of each exterior wall (and
              extensions of the plane thereof in non-glass areas); plus

          (y) Tenant's Allocation of Building Common Areas, as set forth on
              Exhibit E attached hereto for the corresponding floor; plus

          (z) Tenant's Floor Share of all Floor Common Areas.


                                      -81-

<PAGE>



      No deductions from Net Rentable Area shall be made for columns or
projections necessary to the Building, or for vertical penetrations which are
for the exclusive use of Tenant (such as, but not limited to, special elevators
or stairs, mechanical and electrical facilities and air conditioning equipment).
The Net Rentable Area of the Leased Premises has been calculated on the basis of
the foregoing definition and is hereby stipulated for all purposes hereof to the
be amount, expressed in terms of square feet, stated on the Basic Lease
Information sheet.

"Office Section" shall mean that portion of the Building dedicated to office
uses. The square feet of Net Rentable Area included in the Office Section on
each floor of the Building is set forth in Exhibit E.

"Operating Cost" shall have the meaning given in Section 2.04.

"Outline Specifications" shall mean the improvements specified in Schedule III
to the Work Letter.

"Outside Completion Date" shall mean the Estimated Outside Completion Date set
forth on the Basic Lease Information sheet, as the same may be delayed by reason
of any Tenant's Delay.

"Parking Section" shall mean the three (3) levels of below-grade parking located
in the Project, excluding however any Common Areas or Project Common Areas.

"Permitted Use" shall mean with respect to the Leased Premises corporate,
executive and professional office use and all uses accessory thereto as
permitted by law in the Leased Premises of a kind appropriate in a building of
the type and quality of the Building; provided, however, that Permitted Use
shall not include (a) offices of any agency or bureau of the United States or
any state or political subdivision thereof; (b) offices or agencies of any
foreign government or political subdivision thereof; (c) offices of any health
care professionals or service organization which include patient or client
treatment or other on-premises services; (d) schools or other training
facilities which are not ancillary to corporate, executive or professional
office use (excluding, however, the executive offices of such schools or
training facilities which are otherwise consistent with the use of the Building
as a first class office building in Boston); (e) retail or restaurant uses
(except in the Commercial Section and except for facilities limited to the
exclusive use of Tenant's employees and other Tenant Responsible Parties); (f)
radio, television and/or recording studios, or like uses; (g) employment
agencies (excluding, however, the executive offices of such employment agencies
which otherwise are consistent with the use of



                                      -82-

<PAGE>




the Building as a first class office building in Boston); or (h) any use or
activity which is inconsistent with the use of the Building as a first class
office building in Boston, creates a fire hazard or would cause Landlord's
insurance rate to be increased.

"Premium Tenant Improvements" shall mean that portion of the Initial Tenant
Improvements which do not constitute "Building Standard Improvements" or "Excess
Building Standard Improvements", as set forth in the Work Letter.

"Project" shall mean the Building together with the building commonly known as
500 Boylston Street and located on the parcel of land described in Exhibit A-2.

"Project Operational Common Areas" shall mean those areas of the Project located
outside of the Building which service, in whole or in part, the Building,
including, but not limited to central mechanical rooms and loading dock
facilities.

"Project Non-Operational Common Areas" shall mean those areas of the Project
devoted to non-exclusive uses which tenants of the Building have a right to use
in common with other tenants of the Project, including, but not limited to,
walkways, courtyards and landscaped areas.

"Project Common Areas" shall mean the "Project Operational Common Areas" and the
"Project Non-operational Common Areas".

"Rent" shall mean Gross Rent and Additional Rent.

"Rent Commencement Date" shall mean the later of (i) the Scheduled Rent
Commencement Date, or (ii) sixty (60) days after the Completion Date.

"Storage Area" shall mean the approximately 5,032 square feet of storage space
located on floor P3 of the Building, more specifically described on Exhibit C
attached hereto.

"Sublease" shall include any sublease, underletting at any level, tenancy,
concession, license, franchise or other arrangement providing for the use or
occupancy of all or any portion of the Leased Premises.

"Substantial Completion" shall mean (and the Leased Premises or any Expansion
Space, as the case may be, shall be deemed "Substantially Complete") when (i)
installation of the Initial Tenant Improvements or the Building Standard
Improvements required to be provided by Landlord for Expansion Space, as
applicable, has


                                      -83-

<PAGE>




been substantially completed in accordance with the plans and specifications
therefor notwithstanding a requirement to complete "punchlist" items or similar
corrective work which can be completed without causing material interference
with Tenant's use of the Leased Premises for the Permitted Use; (ii) Tenant has
direct access from the street to the elevator lobby on the floor (or floors)
where the Leased Premises are, or the Expansion Space is, as applicable,
located; (iii) Basic Services (as defined in Section 3.01 hereof) and any Extra
Services (as defined in Section 3.02(a) hereof) are available to the Leased
Premises or the Expansion Space, as applicable; (iv) Landlord's architect shall
have issued a certificate of Substantial Completion with respect to the Leased
Premises or the Expansion Space, as applicable; and (v) a temporary or permanent
certificate of occupancy has been issued by appropriate governmental
authorities, permitting use of the Leased Premises or the Expansion Space, as
applicable, and not subject to any conditions which cannot be satisfied without
material interference with Tenant's use of the Leased Premises or the Expansion
Space for the Permitted Use.

"Tenant Affiliate" shall mean a person or entity which controls, is controlled
by or is under common control with Tenant, or an entity into or with which
Tenant is merged or consolidated or to which substantially all of Tenant's
assets are transferred.

"Tenant's Allocation" shall mean an area determined by multiplying the total
square footage of the Building Common Areas by the ratio of the Net Rentable
Area of the Leased Premises (excluding any allocation of Building Common Areas)
to the Net Rentable Area of the Office Section (excluding only the Building
Common Areas).

"Tenant Alterations" shall mean any alterations or physical additions to the
Leased Premises beyond the Initial Tenant Improvements, together with any
painting or decorating of the firestairwells pursuant to Section 4.06 hereof,
any antenna or satellite dish installed pursuant to Section 12.03 hereof, and
any security system installed pursuant to Section 12.04 hereof.

"Tenant's Delay" shall have the meaning attributed to it in the Work Letter.

"Tenant Extra Costs" shall mean the cost of the Excess Building Standard
Improvements and the Premium Tenant Improvements for which Tenant is responsible
pursuant to the Work Letter.

"Tenant Improvements" shall mean the Initial Tenant Improvements and any Tenant
Alterations.





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<PAGE>



"Tenant's Floor Share" shall mean the ratio of Tenant's Useable Area to the
aggregate Useable Area on Tenant's floor.

"Tenant's Personal Property" shall mean all of the furnishings, fixtures,
equipment, effects and personal property of every kind, nature and description
of Tenant and of all persons claiming by, through and under Tenant which, during
the continuance of this Lease or any occupancy of the Leased Premises by Tenant
or anyone claiming under Tenant may be on the Leased Premises or else where in
the Building.

"Tenant's Proportionate Share" is specified on the Basic Lease Information
sheet.

"Tenant Responsible Parties" shall mean all agents, servants, employees,
contractors, licensees and business invitees of Tenant.

"Term" shall mean a period of calendar years, or fractions thereof, commencing
with the Term Commencement Date and ending on the Term Expiration Date stated on
the Basic Lease Information sheet.

"Term Commencement Date" shall mean the date when the Term commences as set
forth on the Basic Lease Information Sheet.

"Term Expiration Date" shall mean the date specified on the Basic Lease
Information sheet when the Term shall end, unless sooner terminated pursuant to
the terms of this Lease.

"Total Leased Net Rentable Area" shall mean the sum of the Net Rentable Area
leased to all Office Section tenants over the course of a year, determined on
the basis of a weighted averaging of the sum of the Net Rentable Area leased to
all Office Section tenants on each day of that year.

"Useable Area" shall mean the Net Rentable Area of the Leased Premises in
question, less the portion of such Net Rentable Area attributable to Floor
Common Areas and Building Common Areas.








                                      -85-

<PAGE>




"Work Letter" shall mean the instrument executed by Landlord and Tenant of even
date herewith attached hereto as Exhibit B governing construction of the Initial
Tenant Improvements.

Other terms used on the Basic Lease Information sheet which is a part of this
Lease, or elsewhere in this Lease, shall have the meaning given them thereon and
herein.

IN WITNESS WHEREOF, the parties hereto have executed this Lease as a sealed
instrument as of the day and year first above written.

                                   "Landlord"

                                   TWO TWENTY TWO BERKELEY VENTURE
                                   a Joint Venture

                                   By: Hines 222 Berkeley Limited
                                       Partnership, Venturer


                                   By: /s/ Gerald D. Hines
                                       -----------------------------------------
                                       Gerald D. Hines, a General Partner


                                   "Tenant"

                                   HOUGHTON MIFFLIN COMPANY, a
                                   Massachusetts corporation

                                   By: /s/ Stephen O. Jaeger
                                       -----------------------------------------
                                       Stephen O. Jaeger

                                   Title:   Executive Vice President and
                                            ------------------------------------
                                            Chief Financial Officer



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