21、 His success was due to ________ he had been working hard.

A. what                        B. the fact which           C. the fact that           D. the fact

20、David decided not to work on the program in the office because she didn’t want her boss to know what she __________.

A. was doing                B. is doing                       C. has done               D. had done

19、America has more than fifty states, ______, Kentucky, is the place _______ Abraham Lincoln was born.

A. one of it; where        B. one of which; where

C. one of that; which     D. one of which; which

18、We are looking forward to ______ another chance ______ it again.

A. be given; to try          B. give; to try                C. giving; trying         D. having; to try

17、 ―Most people think the rabbit is a beautiful, gentle animal which can run very fast.

―_____________.

A. So does it                 B. So it does                 C. So it is                     D. So is it

16、--I want to know if I _______ smoke here.

--No, you _______. Couldn’t you see the sign "NO SMOKING" there?

A. can; needn't             B. must; can't              C . may; mustn't       D. shall; won't

15、I’ll leave Changsha for Beijing ______ a week, while my brother will leave Beijing for Changsha ______ our National Day.

A. in; in                       B. after; in                   C. after; after             D. in; after

14、 I rang up my parents and then grandparents last night. To my disappointment,        of them answered it.

A. either                       B. none                            C. neither                  D. all

13、 ______ your composition carefully, some spelling mistakes can be avoided.

A. Having checked             B. If you check          C. Check                    D. To check

12、______ March 12th, the students were planting trees on the hill.

A. There being　　        B. It was　                   C. It being　　           D. This was