20. ---Excuse me, Professor Smith, I was wondering if I could leave a quarter earlier today.

　 ---________.

A. Nothing the matter　 　　　　　　　　　　　　　　　　　 　B. Sure, go ahead　　

C. Oh, why not?　　 　　　　　　　　　　　　　　　　　　　　 　D. Of course, no problem

19. Some students remember a lot of knowledge but can’t recognize ways to use it in new _________.

　　 A. conditions　　　　 　　 B. cases　　　　　　　　　　　　 C. backgrounds　　　　　 D. situations

18. I passed by the sports field the other day, ______ there was a football match going on then.

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

17. Mrs Jones asked the driver to _________ his son at the library on his way downtown.

A. drop in　　 　　　　　　 B. drop out　　　 　　　 C. drop off　　 　　　　　 D. drop by

16. Over the Changjiang River _______ four grand bridges in Wuhan by now.

　　　 A .have been built　　　　 B. have built　　　　　　　　 C. has been built　　　　　 D. has built

15. The local Tibetans and Sherpas laughed at the strange bottles containing ________ they referred to as “English air”.

A. which　　　 　　　　　　 B. that　　　　　 　　　　 C. how　　　　 　　　　　 D. what