21. I’m looking for a babysitter (保姆) . She must be _______ too old _______ too young .

　 A. neither ; nor　　　 B. both ; and　　 C. either ; or　　 D. not only ; but also

20. Study hard , _______ you’re sure to have a good result in the exam !

　 A. but　　　 B. and　　　 C. for　　　 D. or

19. _______ he was out of the room , he turned back and knocked at the teacher’s door again .

　 A. Before　　　　 B. Since　　　　 C. As soon as　　　　 D. Until

18. - I’m going to Hangzhou for a holiday this weekend .

　 - _______ you are there , can you buy me some green tea ?

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

17. Hurry up , _______ we will miss the trian .

　 A. but　　　 B. and　　　 C. or　　　 D. so

16. Lucy has seen the film , _______ Lily hasn’t .

　 A. and　　　 B. or　　　 C. but　　　 D. so

15. There’s ______ on the moon.

A . no air but water　 B. not any air or water C . not any air and water 　D. no air or no water　

14. I don’t know _______ this evening.

A.　 if he will be free 　B.　 whether he is free　 C .　 when he is free 　　D.　 when is he free

13. ___ I looked for my toy, I could not find it.

A.　 But　 B.　 Yet　 C.　 Because　 D.　 However

12. I’ll offer some bread to Li Ming. Li Ming,_______, may not want it.

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