15. I won’t tell the student the answer to the math problem until he ________ on it for more than an hour.

　　　 A. has been working 　 B. will have worked 　　 C. would have worked 　　 D. had worked

14. Little ________ that his shoes could be sold for 150,000 yuan at the auction (拍卖).

　　　 A. Liu Xiang expected 　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　 B. Liu Xiang had expected

　　　 C. did Liu Xiang expect 　　　　　　　　　　　　　　　　 D. had Liu Xiang expected

13. -No wonder you caught a cold. You ________ out last night without a coat. 　 -I know how silly I was.

　　　 A. shouldn’t have gone 　　　　　　　　　　　　　　　　 B. mustn’t have gone

　　　 C. couldn’t have gone 　　　　　　　　　　　　　　　　　 D. mightn’t have gone

12. -Why on earth didn’t you answer the phone?　 -I’m sorry, but the doorbell __________ too.

　　　 A. is ringing 　　　　　　　 B. was ringing 　　　　　　 C. rang 　　　　　　　　　　　 D. was about to ring

11. ________ the whole passage, so that you will get a general idea of it.

　　 A. Scanning 　　　　　　　 B. To scan 　　　　　　　　　 C. Scan　　　　　　　　　　　 D. Having scanned

10. William Beebe, one of the first men ________ the depth of the sea in a bathysphere, got interested in oceanography because of one book.

　　　 A. exploring 　　　　　　　 B. having exploring 　　 C. to be exploring 　　　 D. to explore

9. A clear, warm day suddenly grew chill ________ a dark curtain of rolling dust advanced across the plains.

　　　 A. until　　　　　　　　　　　 B. as　　　　　　　　　　　　　 C. so　　　　　　　　　　　　　 D. since

8. --- Have you gone over what the teacher taught in class?　　　 　　--- Not yet.

　 --- Better remember: __________.

A. Don’t count your chickens before they’re hatched　 B. A bird in hand is worth two in the bush

C. Strike while the iron is hot　　　　　 D. All roads lead to Rome

7. --- Did your father phone you shortly after the accident?

　 --- No, it was a fortnight _________ he gave me a phone call.

A. since　　　　　　　　　　　　 B. when　　　　　　　　　　　 C. while　　　　　　　　　　　 D. before

6. We ________ ; we followed the boss into the hall as his guests. How lucky we were!

A. didn’t need to wait　　　　　　　　　　　　 　　　　　　　 B. needn’t have waited

　 　　 C. must have waited　　　　　　　　　　　　　　　　　 　　　 D. couldn’t have waited