四级语法系列练习－助动词、情态动词(1)

Unit 2 助动词、情态动词(一)

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

2. You _____ her in her office last Friday; she's been out of town for two weeks.
A. needn't have seen
B. must have seen
C. might have seen
D. can't have seen

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。

2. D
译文：上星期五你不可能在办公室见到她，她去外地已有两星期了。
本句是情态动词表示推测的用法。

3. C
译文：玛丽的考试成绩全班第一，她学习一定很刻苦。
本句是情态动词表示推测的用法。表示对过去发生情况的肯定的推测。

1 mess   

vt.将…弄糟，混乱，妨碍，使紊乱；n.食堂，伙食，用膳，一份食品，混乱，乱七八糟，困境

参考例句：

• Don't mess up my homework.不要弄乱我的家庭作业。
• You'll mess up my hair.你会把我的头发弄乱.

2 ought   

v.aux.应该，大概；n.责任

参考例句：

• Ought I to hand in the homework today?我应当在今天交上作业吗？
• They ought to be here by now.他们这个时候该到了。