2011年三级语法讲义(20)

成人学士学位英语学习资料

第五章 情态动词

must: 表示推测，有三种形式：must do; must be doing; must have done.

e.g. Judging by his accent, Ann must be from the North America.

My aunt must be at the library.

My tutor must be correcting my paper.

The professor must be doing preparation for tomorrow’s lesson at home now.

The manager must have been very angry at the meeting because his employee said some tactless

words.

---Linda has gone to work, but her bicycle is still here.

---She must have gone by bus.

---Must I start out no？

---No, you needn’t. (No, you don’t have to.)

---Yes, you must.

I must go now.

I have to go now.

We’ll have to reconsider the matter.

We must tide up the room every day.

情态动词+have+过去分词

情态动词用来表示能力、允许、许诺、可能、劝告、意愿等概念或态度。情态动词无人称

变化，在句子中和动词原形一起构成谓语。根据这几年的考试看，着重测验情态动词接完成

时的用法。

1. may (might) have + done sth, can (could) have + done sth

表示过去，推测过去时间里可能发生的事情。

e.g. Philip may (might) have been hurt seriously in the car accident.

Philip can (could) have been hurt seriously in the car accident.

2. ought to have done sth, should have done sth

本应该做某事，而事实上并没有做。否定句表示"不该做某事而做了"。

e.g. You ought to (should) have been more careful in this experiment.

He ought not to have thrown the old clothes away.（事实上已扔了。）

ought to 在语气上比should 要强。

3. needn’t have done sth

e.g. The film actor brought a lot of clothes when he went to the seaside.

But actually he needn't have done so, because it was hot there.

4. had better表示最好

had better 相当于一个助动词，它只有一种形式，它后面要跟动词原形。

had better do sth

had better not do sth

e.g. It is pretty cold. You'd better put on your overcoat.

She’d better not play with the dog.

历年真题：

1. Since this road is wet and slippery this morning, it _____ last night. (2004-11-35)

A. must rain B. was raining