17.More than a dozen students in that school _____ around to

study medicine last year.

A. sent B. were sent C.had sent D. had been sent

18.At last, we found ourselves in a pleasant park with trees providing shade and ______down to eat our picnic lunch.

A. sitting B. having sat C. to sit D. sat

19.My brother is an actor .He ______ in several films so far.

A. appears B. appeared C. has appeared D. is appearing

20.—Are you still busy ?

—Yes,I ______ my work,and it wont’t take long .

A. just finish B. am just finishing

C. have just finished D. am just going to finish

21.With more forests being destroyed,huge quantities of good earth _____ each year.

A.is washing away B.is being washed away C.are washing away D are being washed away

22.The country life he was used to _____ greatly since 1992.

A.change B.has changed C.changing D. have changed

23. _What’s wrong with your coat ?

_Just now when I wanted to get off the bus,the man next me ______ on it .

A. sat B. had sat C.had been sitting D. was sitting