31.The boy was observed __________ basketball at eight o’clock yesterday.

　 A. playing　　 B. play　　 C. to play　　 D. having played

30. _______the youth to the rising sun, Mao Zedong paid more attention to the problems that the youth were faced with.

　 A. Compared　　　 B. Comparing　　　 C. To compare　　 D. Being compared

29. My uncle ____________ in Beijing for over 10 years. Now he lives in his hometown in Xuyi.

　 A. has worked　 B. worded　　　　 C. had worked　 D. works　　

28. Peter said he ______ when he got there but we have never heard from him since then.

　 A. was writing　　 B. would write　　　 C. had written　 D. has been writing

27. The project is reported __________ 3 months ago.

　 A. to complete　 B. to be completed　 C. to have completed　 D. to have been completed

26. American Indians _______ about five percent of the U.S population.

　 A. fill up　　 B. bring up　　 C. make up　　 D. set up

25. Gun control is a subject _______ Americans have argued for a long time.　

　 A. of which　　 B. with which　　 C. about which　　 D. into which

24. The moment I got home, I found I ______ my jacket on the playground.

　 A. had left　　 B. left　　　 C. have left　　 D. was leaving

23. I’d like to work with _______ is honest and easy to get on with.

　 A. who　　　 B. whomever　　 C. whoever　 　　D. no matter who

22. I won’t tell the student the answer to the math problem until he ________ on it for more than an hour.

　 A. has been working　　 B. will have worked　　 C. will have been working　 D. had worked