Page 28 of the Cover Letter Tutorial
Avoid Weak and Passive Verbs:
Make yourself sound as active and in control as possible. Don’t make it sound as though your accomplishments in school and previous jobs just happened or that someone else should get credit for them.
Show how you took an active role in making them happen.
Follow this link to see some examples of how to avoid passive voice in cover letters.
Lost? Check out the Map to the Cover Letter Tutorial… or go to the home page of the Cover Letter Tutorial for Developing Stunningly Effective Job-Search Cover Letters.