21. It's not          good idea to drive for four hours without           break .

A. a; a             B. the; the           C. a; the             D. the; a

22. Not only my sister but also I ______ interested in the novel for a long time.

A. have become       B. has become       C. have been         D. has been

23.---David certainly cares too much about himself.
---Yes. He’s never interested in what _________ is doing.
 A. no one else              B. anyone else             C. someone else         D. nobody else

24. One hundred yuan for a bowl of noodles, you ________ be joking!

    A. may                 B. can                 C. need               D. must