Il.单项选择【共15小题；每小题1分，满分15分）
16. Jumping out of______ airplane at ten thousand feet is quite_____exciting experience.
A. an; an B./; the C./; an D. the; the
17. Mr. Smith was thinking about how to explain to the manager why he was late for work, when
a good idea______ to him.
A.happened B.brought C.occurred D.struck
18. The______of cool air comin from the air condition made me fecl vcry comfortable.
A.flow B.column C.flood D.currcnt
19. Please________the litter on your way to school.
A. pick up B. take up C. make up D. turn up
20. - The earthquake last night was really terrible,
-________, no people were killed, and they escaped in time.
A. Luckily B. Hopefully C.Sadly D. Unformaunately
21. Gun controlis a subject______Americans have argued for a long time.
