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

A. a£»a     B. the£»a      C. the£»the      D. a£»the

22. ------ How about putting some pictures into the report?

------        A picture is worth a thousand words.

A. All right?      B. No way.  C. Why not?     D. No matter.

23. This is the house _________ windows face the south.

A. which       B. what’s     C. where      D. whose