四级语法系列练习－助动词、情态动词(1)

（单词翻译:单击）

1. The room is in a terrible mess¹; it _____ cleaned.
A. can't have been
B. shouldn't have been
C. mustn't have been
D. wouldn't have been

3. Mary's score on the test is the highest in her class, she ____ have studied very hard.
A. may
B. should
C. must
D. ought² to


答案：
1. A
译文：房间里乱七八糟，一定没打扫过。
本句是情态动词表示推测的用法。情态动词may, might, must, can 和could 可用来表示推测。can 和could 通常用于否定句或疑问句中，may, might和must用于肯定句中，表示对现在、将来及过去情况进行肯定的推测。