—I called you at 9 last night，but no one answered.—Sorry，I ________ sleeping.I w

题型：不详难度：来源：

—I called you at 9 last night，but no one answered.
—Sorry，I ________ sleeping.I went to bed very early.

A．need have been	B．would have been
C．must have been	D．should have been

答案

解析

C
解析　根据答语中的“I went to bed very early”可知，此处为肯定推测，用must，表示问话人打电话时，答话人一定正在睡觉。must have done表示过去肯定做了某事。