5. you have made a mistake--- you’ve _______the letter.

4. I should never have____________ becoming a drug user.

3. The department was badly organized until she____________ it.

2. The possibility of his stealing money from class can not be _________, for no evidence can prove his absence at that time.

1. The local government has ________ a campaign against bird flu.

8.　　　　　 With hard work, our class has made great _________(progressive) in maths study.

7.　　　　　 　We have conducted a lot of survey on animals’ eating habits__________ (late).

6.　　　　　 Some university students show no interest in literature while Jack and Mary have ________(similarity) tastes in it.

5.　　　　　 The big earthquake has further____________ (strength) my determination to be a volunteer to help the people in Sichuan.

4.　　　　　 To our surprise, the young woman was the__________ (murder) who has killed her parents.