15. We were under no ……..…………  about how difficult it would be to achieve our aims.

A. illusions                         B. daydreams                    C.fantasies                        D. deceptions

16.The Thai live ……..…………  farming on their burnt-over land and wet-rice terraced fields.

A. in                                   B. for                                  C. with                               D. on

17. Debris was ……..………… for miles after the tornado touched down late Saturday.

A. evacuated                     B. collapsed                       C. scattered                       D. trapped

18. You……..………… look at other students’ work. It’s against the rules.

A. don’t have to                 B. mustn’t                          C.can’t                               D.shouldn’t

19.John:“Do you think that we should use public transportation to reduce pollution?”

      Laura: “……..…………”

A. Yes, it's an absurd idea.                                          B. I couldn’t agree with you less.

C. Well, I can’t agree with you more.                          D. Of course not. You bet.

20. He doesn’t seem to be successful ……..…………  hard he works.

A. whatever                       B. though                           C. but                                 D. however