21.A.passed along　　 B. passed down　　 　C. went by　 　　D. went over

19. He is very popular among his students as he always tries to make them _______ in his lectures.

　 A. interested　　　　 B. interesting　　　　 C. interest　　　 D. to interest

18. – Can I smoke here ?

　 -- Sorry. We don’t allow ________ here.

　 A. people smoking　　 B. people smoke　　 C. to smoke　　　 D. smoking

17. At the end of the meeting, it was announced that an agreement ________.

　 A. has been reached　 B. had been reached　 C. has reached　 D. had reached

16. The flowers were so lovely that they __________ in no time.

　 A. sold　　　　 B. had been sold　　　 C. were sold　　　　 D. would sell

15. ---How’s your tour around the North Lake? Is it beautiful?

　 ---It ________ be, but it is now heavily polluted.

　 A. will　　　　 B. would　　　　 C. should　　　 D. must

14.　 ---It’s a long time since I saw my sister. 　---_______________ her this weekend?

　 　A. Why not visit　　　　　　　　　 B. why not to visit

　 　C. Why not visiting　　　　　　　　 D. Why don’t visit

13.　 It is reported that the floods have left about _________ people homeless.

　 　A. two thousand　　 B. two-thousands　　 C. two thousands　　 D. two thousands of

12.　 If the firms failed to make enough money, they would 　　　　　.

A. close down　　　　　　　 B. call off　　　　　　　　　　 C. turn down　　　　　　　　 D. set off