15. It has been proved ___ eating vegetables in childhood helps to protect you against serious illnesses in later life.

　A. if　　　　　　　　　　 B. because　　　　　　　　 C. when　　　　　　　　　　　　　　 D. that

14. We went through a period ___ communications were very difficult in the rural areas.

A. which　　　　　　　　　　 B. 　 in which　　　　　　　　　　 C. whose　　　　　　 D. with which

13. The health official said ____ 12 suspected cases of influenza A(H1N1)were tested negative and ___, so far, this city has reported no case of the virus.

A. what; that　　 　　 B. that; what　　　 C. 不填; that　　 　 D. that; 不填

12. Ten years ago the population of our village was_________ that of theirs.

A. twice as much as　　　　　　　　 　　B. twice as large as

C. as twice large as　　　　　　　　　　 D. as twice much as

11. The newly-built skyscraper, 　　　　　, is thought the first one in this city.

A．one hundred and twenty-five meters as high as

B．as one hundred and twenty-five meters as high

C．as high one hundred and twenty-five meters as

D．as high as one hundred and twenty-five meters

10. What lessons China can draw from 　　　　　financial crisis(金融危机)in the United States has become 　　　　　hot topic in Beijing.

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

9. The mother opened the door quietly so as not to ______ the sleeping baby.

A. upset　　　 　　　　　 B. interrupt　　　 　　　　　　 C. disturb　　　　 　　 D. release

8. -I didn’t know you were good friends.

-You　　 . I have known her since she moved here. You were studying abroad then.

A．may have　　 　 B．couldn’t have C． needn’t have　 D．must have

7. I would appreciate ______, to be frank, if goods could be delivered as soon as possible.

A. you　　 　　　　 B. this　　 　　　　　　　　 C. myself　　 　　　　　　 D. it

6. In 1948, three American scientists invented ______ transistor, which is ______ small electronic device to control an electric current.

A. the; a　　　　　　　　　　 B. a; a　　　　　　　　　　　　 C. the; the　　　　　　　　 D. a; the