21. —I'm not good at singing£¬you know.

—        It's just for fun.

A. No problem.     B. Come on!    C. What a pity!   D. Cheer up.

22. Mary asked me to repeat     telephone number       second time so that she could write it down.

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

23. According to an old proverb£¬a red sky at night often        fine weather the next day.

A. indicates    B. impresses    C. obtains   D. exposes