Question

【题目】—I saw your mother in the library just now.—It ______ be her. She went to Beijing yesterday.
A.can't
B.mustn't
C.needn't

Answer 1

【答案】A
【解析】句意：－我刚才在图书馆里见到你妈妈了。－那不可能是她。她昨天去北京了。A. can't不能，不可能；B. mustn't不准，禁止；C. needn't不必。本句表示推测，因为昨天去了北京，所以“不可能”是好。故选A。