21. May I take the magazine out of the library? Sorry, you __________.
A. might not B. needn’t C. mustn’t D. may not
22. ---Must I leave for Beijing at once? ---No, you __________.
A. can’t B. needn’t C. mustn’t D. may not
23.______ she wait inside or outside?
A. Shall B. Will C. Would D. May