Common use of Twenty Clause in Contracts

Twenty. First Amendment to Second Amended and Restated Limited Partnership Agreement of Corporate Office Properties, L.P., dated July 20, 2006 (filed with the Company’s Current Report on Form 8-K dated July 26, 2006 and incorporated herein by reference).

Twenty. First Second Amendment to Second Amended and Restated Limited Partnership Agreement of Corporate Office Properties, L.P., dated July 20January 9, 2006 2007 (filed with the Company’s Current Report on Form 8-K dated July 26January 16, 2006 2007 and incorporated herein by reference).