Question

【题目】-- Someone is knocking at the door.
-- Who ______ it be at this hour of day?
A.may
B.can
C.must
D.should

Answer 1

【答案】B
【解析】句意：—有人在敲门。—这个时间了，可能是谁呢？may可能，用于肯定句；can可能，用于否定句和疑问句；must一定；should应该。这是特殊疑问句，根据句意可知选B。