17. I was walking along the river ____ I heard a cry for help. 　　 A. while　　 B. since　　　 C. when　　 D. As

16. ____ we have come, let’s stay and enjoy it. 　 A. For　　 B. As　　　 C. Because　　　 D. Since

11. . ____, he is good at drawing. 　 A. To be a child　　 B.A child as he is　　 　 C. As a child　　　　 D. Child as he is 12. Don’t be discouraged ____ you have fallen behind others. 　 A. whether　　　 B. as if　　 C. even if　　 D. however 13.These planes can fly ____ than the old ones. 　A. as fast three times　　 B. three times as fast　 　 C. three times fast　　　　 D. three times faster 14. ____ had the bell rung ____ the students took their seats. 　 A. Hardly；when　　　 B. No sooner；when 　 C. Hardly；than　　　 D. No sooner；then 15. ____ many times，but he still couldn’t understand it. 　 A. Having been told　　　 B. Though had been told 　 C. He was told　　　　　　 D. Having told　

10. . I was about to leave my house ________ the phone rang. 　　 A. while　　　 B. when　　　 C. as　　　 D. After

9. . We must hurry up ______ catch the last train. 　　 A. that　　　 B. so that to　　　 　　 C. in order that　　　 D. in order to

8. . You will be late _____ you leave immediately. 　　 A. unless　　　 B. until　　　 C. if　　　 D. Or

7. . Although it’s raining,　 _____ are still playing football on the playground. 　　 A. they　　　　 B. but they　　　 C. and they　　　 D. so they

6. . I always keep candles in the house _____ there is power cut. 　　 A. if　　　　 B. in case　　　 C. unless　　　 D. in case of

5. . He will never succeed _____ hard he tries. 　　 A. whatever　　　 B. despite　　　 C. though　　　 D. However

4. .The water will be further polluted unless some measures _____. 　 A. will be taken　　 B. are taken　　　 　 C. were taken　　　　 D. had been taken