20. This printer is of good quality. If it _______ break down within the first year, we would repair it at our expense.

A. would　　 　　　　　　 B. should　　 　　　　　　　 C. could　　 　　　　　　 D. might

19. The teacher asked us to write a ________ article.

A. 700 word　　　　　 B. 700-words　　　　 C. 700’s words　　　　 D. 700-word

18. I used to be a very delighted girl. I guess no human being could have passed _______ childhood.

　 　 A. a happy　　 　　　　　 B. a happier　　 　　　　　 C. the happier　　 　　　 D. the happiest

17. The new outline will throw light _______ students’ understanding of history.

　 　 A. upon　　　　 　　　　　 B. at　　　　　　 　　　 C. of　　　　　　 　　　 D. over

16.　 --- Well, Linda, I’m sorry but I have to leave.

--- _______. I hope to hear from you soon.

A. So am I　　　　　 　 B. Enjoy yourself　　　 C. Don’t be so sad　　 　　　 D. Keep in touch

15. Researchers _______ to develop vaccines and this will probably take several months to complete.

A. are working　 　　　　 B. worked　　　 　　　　　 C. will work　　　　 　 D. has worked

14. Water can absorb and give off a lot of heat, thus ________ a stable enviroment.

　　 A. creating　　　　　 B. to creat　　　　　 　 C. created　　　　　 D. being careated

13. He took ________ advantage of cultural resouces and succeeded in ________ 1990s.

A. an ; /　　　　　　 B. the ; the　　　　　 　　　 C. an ; the　　　　　 D. / ; the