第十一讲 情态动词

Crack English Series ®

1 第十一讲 情态动词

1. can 的用法

a. 表能力。

Some of us can use the computer now, but we couldn’t last year.

b. 表示惊异、怀疑、不相信的态度。（主要用于否定句、疑问句和惊叹句中）不耐烦、难道会，究竟

Can this news be true?

It can’t be our headmaster.

He’s gone to Beijing.

How can you be so foolish!

How can you say you really understand the whole story.

If you have covered only part of the article?

c. 用于肯定句表推测时，指理论上的可能性，并不涉及是否真的发生。

Children can sometimes be very naughty.

Accidents can happen on such days.

It can be very cold here, even in May.

d. 惯用形式 cannot …too…表示无论怎么… 也不为过

You cannot be too careful when you cross the road.

e. can和be able to 都表示能力，在意思上没有区分。但can只有现在时和过去时，而be able

to 可以用一般过去时，将来时，完成时。此外，当表示过去成功做了某事的时候，只能使用be able to 结构。不能使用could

My son has been able to play the piano since he was eight.

I’ll be able to speak French in a few months.

Mary could (was able to )dance well before she went to school.

The fire was very big, but most people were able to escape from it.

2. must 常考用法

a. mustn’t 表示禁止(易与can’t混淆)

You mustn’t drive so fast in the street.

b. 表示有把握的推测

It must be our headteacher.

You must be hungry after a long walk.

There must be hole in the wall.

c. 偏要, 一定

Must you play the piano at midnight?

-----Who is the girl standing there?

-----Well, if you must know, her name is Mabel.

d. 用作名词：必须的东西

The English language has already been a must for the young.

3. shall 的常考用法 a. 用在一三人称疑问句中，表示征求意见

Shall we begin our lesson?

Shall the driver wait?

When shall my father be able to leave hospital?

b. 用于第二三人称陈述句中，表示说话人给对方的命令，警告，允诺或威胁

You shall go with me. (命令)

You shall have the book when I finished it. (允诺)

He shall be punished.(威胁)

4. should常考用法

a.表示根据某种迹象推测， 可以用在否定句中

I feel the floor shaking, it should be a an earthquake.

There shouldn’t be any difficulty about passing the road test since you have practiced a lot

in the driving school.

b.竟然

It’s a pity that he should have failed in the exam.

5. would do 和used to do的用法及区别

两者都表示经常做某事，后者只表示过去经常做某事，暗指现在已不这样

He used to be a naughty boy.

He used to make a lot of troubles.

The mother would serve the breakfast to his son every morning.

6.need的用法

Need 在疑问句和否定句中，多为情态动词，后接动词原形；在肯定句中为实意动词，后接to do.

You needn’t ask him the question.

---Need I finish the work before ten?

---Yes, you must.

---No, you needn’t.

You need to put on special clothes when you try to go through the fire.

You don’t need to list everything.

7. 情态动词+have的用法

a. must have done表示对过去已经发生的行为进行推测，意为：想必、准是、一定（过去）做了某事。

It must have rained last night, for the road was quite muddy.

The lights were out, they must have been asleep.

b. cannot have done表示对过去发生的行为的怀疑和不肯定

He cannot have forgotten it.

他不可能忘记它。

c. could have done可用于肯定句中，表示“可能已经…”之意，此外，还可以表示过去有实现的的可能性，意为“本来可以… Crack English Series ®

2 You could have done better, but you were too careless.

I saw Mr. Wang just now. He couldn’t have gone to Beijing.

d. may/might have done表示对过去已发生行为的推测，意为“也许、或许、已经（没有）…”一般只用于肯定句或否定句中，不用于疑问句。用might则表示语气更加不肯定。

You should not have swum in that sea.

You might have been eaten by fish.

You might have given him more help, though you were busy.

e. should/ought to have done 表示本该做而实际未做

You should have come to the meeting earlier.

You shouldn’t have told her the truth.

He ought not to have treated his parents like that.

f. needn’t have done 表示本来不必去做而实际做了。注意didn’t need to do 表示没有必要做而实际上也没有做。

You needn’t have taken a taxi here, for it was very near to my house.

I didn’t need to clean the windows. My brother did it.

情态动词

1.(NMET 2003北京春季,21) —The room is so dirty._______ we clean it

—Of course.

A.Will B.Shall C.Would D.Do

2.(2003上海春季, 24) My English-Chinese dictionary has disappeared. Who _______ have

taken it

A.should B.must C.could D.would

3.(NMET 2002, 25)—Is John coming by train

—He should, but he _______ not.He likes driving his car.

A.must B.can C.need D.may

4.(NMET 2002 北京, 31) — I heard they went skiing in the mountains last winter.

— It _______ true because there was little snow there.

A.may not be B.won't be

C.couldn't be D.mustn't be

5.(2002 上海, 27) It has been announced that candidates _______ remain in their seats until

all the papers have been collected.

A.can B.will C.may D.shall

6.(NMET 2002 北京春季, 29) — I hear you've got a set of valuable Australian

coins._______ I have a look

— Yes, certainly.

A.Do B.May C.Shall D.Should

7.(2002 上海春季, 28) Oh, I'm not feeling well in the stomach, I so much fried chicken just now.

A.shouldn't cut11 B.mustn't have eaten

C.shouldn't have eaten D.mustn't eat

8.(NMET 2001, 33) I was really anxious about you.You _______ home without a word.

A.mustn't leave B.shouldn't have left

C.couldn't have left D.needn't leave