Question

【题目】— Listen! Someone is knocking at the door. Who can it be?
— It _______ be Tom. He said he would visit me this evening.
A.can't
B.need
C.must
D.mustn't

Answer 1

【答案】C
【解析】句意：——听！有人正在敲门。可能会是谁了？----也许可能是Tom.他打过电话说今晚要拜访我。A. can't 不可能；B. need需要；C. must一定；D. mustn't禁止，千万别。根据句意可知，此处表示否定的推测，答案为C。
考查情态动词用法。