20. -The Mars-500 test will take about 520 days.

-__________ 　I hope it goes well.

A. It’s a pleasure.　 　B. Good luck! 　　C. That’s OK.　　 D. Congratulations!

19. Tom _______ the USA. He _______ back in two months.

A. has gone to; comes　　 　　　　　　　 B. has gone to; will be 　　

C. has been to; comes 　　　　　　 　　　 D. has been to; will be　

18. -I don’t know _______ now.

　 -She is much better today.

A. how is she　 　 B. where is she　 　 C. how she is　 　　　　　 D. where she is　　

17. _______ they are twin brothers, they don’t look like each other.

A. Though　 　　 B. Since　 　　　　　 C. However　 　　　 D. When　　

16. -Do you mind if I smoke here?

　 -_______ You can go to smoke in the next door.

A. Yes, please.　 　　　 B. Never mind.　 　 C. You’d better not. 　D. Of course not.

15. Sandy didn’t tell her parents that she was going home because she wanted to give them a _______.

A. gift　　 　　　 B. call　 　　　　　　　 C. surprise　　 　　 D. note　　　　

14. This is _______ difficult problem that few students can work it out.

A. so　 　　　 　　　 B. so a　 　　　 　　　 C. such　 　　　 　　　 D. such a　 　

13. It’s nice 　_______ Andy _______ me with my English study.

A. at; to help　 　　 B. of; to help　 　　　 C. with; help　 D. of; help　

12. We will fly a kite as soon as your homework _______.

A. finishes　 　 B. will be finished　 　　 　C. has finished　 　　　 D. is finished