笫二部分：英语知识运用（共两节，满分25分）
第一节：单项填空（共10小题i每小题1分，满分10分）
从A..B.C.D四个选项中，选出可以填入空白处的最佳选项。
16. -I've decided to buy a new watch..
-______you've had a good one.
A．How come? B．Up to you.
C．Why not? D．What about?
17. My idea is_____we should go to help him out at once.
A. what B.it C.which D.that
18. Be careful when you cross this very busy street_______. you may get run over by a car.
A. If possible B.If not C.If necessary D. If so
19. It was not until mid-night_______he went back home after the experiment.
A. when B.／ C.that D.before
20. No sooner had I come to the office________the boss told me that I was fired.
A. when B. after C. than D. before
21. The police came in_______the thief attempted to rush out of the store.
