Question

【题目】I __________ asleep because it took me a long time to realize that the telephone was ringing.

A. could have fallen B. should have fallen

C. must have fallen D. mustn't have fallen

Answer 1

【答案】C

【解析】考查情态动词。句意：我一定是睡着了，因为过了好一会儿我才意识到电话铃在响。must have done“过去一定做了……”表对过去的肯定推测。