21. ---- I’ll go camping this weekend.
---- ________
A. Don’t give up now. B. No, I’m too busy. C. Have a good time. D. Can you fish?
22. Excuse me, but can you tell me _______?
A. where can I get to the library B. where I can get to the library
C. how can I get to the library D. how I can get to the library
23. It was not until she got home Mary realized she had lost her keys.
A. that B. when C. where D. before
