21. ______ on, and you will succeed in solving the problems.

　 A. To keep　　 　　　 B. Keeping　 C. Keep　　 　　　　　 D. Having kept

20. -I’m going to the post office.

　 -_____you’re there, can you get me some stamps?

　 A. As　　 　　　　　　 B. While　　 　　　 C. Because　 　　　　　　　 D. If

19. Why do you want a new job______ you’ve got such a good one already?

　 A. that　　 　　　　　　 B. where　 　　　　　 C. which　　 　　　　 D. when

18. After the war, a new school building was put up ______ there had once been a theatre.

　 A. that　　 　　　　　　 B. where　　 　　　 C. which　　 　　　 D. when

17. ______ we’ll go camping tomorrow depends on the weather.

　 A. If　　 　　　　　　　　　　 B. Whether　　 　　 C. That　　 　　　　　 D. Where

16. If we work with a strong will, we can overcome any difficulty, ______ great it is.

　 A. what　　 　　　　　 B. how　　 　　　　 C. however　　 　　 D. whatever

15. Would you like a cup of coffee ______ shall we get down to business right away?

　 A. and　　　 　　　　 B. then　　 　　　　　 C. or　　 　　　　　　　 D. otherwise

14. She thought I was talking about her daughter, ______, in fact, I was talking about my daughter.

A. whom　　 　　　　　　　 B. where　　 　　　 C. which　　 　　　 D. while

13. Although brought up in China, ______ he is well known for his novel about Russia.

　 A. however　　 　　 B. and　　 　　　　　　 C. but 　　　　　　　 D. yet

12. Mother was worried because little Alice was ill, especially ______ Father was away in France.

A. as　　 　　　　　　 B. that　　 　　　　　 C. during　　　 　　 D. if