【题目】 My room is a mess, but I __________clean it before I go out tonight. I can do it in the morning.
A.daren't
B.shouldn't
C.needn't
D.mustn't

【答案】C
【解析】我的房间很乱，但是在今天晚上出门前我不必打扫，我上午可以做。daren't不敢；shouldn't不应该；needn't不必；mustn't必须不；一定不要（表禁止）。根据后一句I can do it in the morning可知选C。