21. He has two sons, __________ work as chemists.

A. two of whom

B. both of whom

C. both of which

D. all of whom

20. He must be from Africa, __________ can be seen from his skin.

A. that　　　　　 B. as　　　　　 C. who　　　　　　 D. what

19. Is it in that factory __________ “Red Flag” cars are produced?

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

18. May the fourth is the day __________ we Chinese people will never forget.

A. which　　　 B. when　　 C. on which　　　　 D. about which

17. It’s the third time __________ late this month.

A. that you arrived　　 B. when you arrived　

C. that you’ve arrived　 D. when you’ve arrived

16. The train __________ she was travelling was late.

A. which　　　　　　　 B. where　　　　　 C. on which　　　　　 D. in that

15. Mr. Zhang gave the textbook to all the pupils except __________ who had already taken them.

A. the ones

B. ones

C. some

D. the others

14. ---- “How do you like the book?”

---- “It’s quite different from __________ I read last month.”

A. that

B. which

C. the one

D. the one what

13. Is there anything __________ to you?

A. that is belonged

B. that belongs

C. that belong

D. which belongs

12. Didn’t you see the man __________?

A. I nodded just now　

　B. whom I nodded just now

C. I nodded to him just now　　　　　　　　　 D. I nodded to just now