情态动词的用法

A. can; could; be able to

Can 

1. 表示“能力”(此时过去时是could)   I can swim.

2.表示许可、请求，“可以”。--Can/Could I go now? –You can leave now.

3 表示推测, 把握很大,could也可表推测,把握比can小。此时can和could时间上无差异。

--Look! Someone is coming! Who can it be?

--It can’t be him. He has gone to Paris.（不可能）/ He could be here soon.  

4 表示感情（惊异/不耐烦）“究竟，到底”（主要用于否定句，疑问句和感叹句中。）

How can you be so foolish?

What can it possibly be? 到底那是怎么一回事?

They can’t be working at this time of day.

5 肯定句中客观存在的可能性。“有时会，偶尔”

It can be quite hot there, especially in summer.

☆can’t … too…/ can never … too… 表示“无论…都不过分”、“越…越好”

You can never be too careful when crossing the road.

Could  

1.表示能力， can 的过去式，过去能够

Could you speak English then? 那时候你会说英语吗?

2. 请求允许（委婉语气）（问句的答语不用could，而用can，）

Could [Can] I use your pen? ” “Yes, of course you can.”/ No, I’m afraid not.

3. 表示推测可能性（肯，否，疑）

We could go there this summer. 今年夏天我们可能要去那儿。(将来可能性)

You could be right, but I don’t think you are. 你可能是对的，但我并不认为你是对的。

4. could have done ①对过去推测，可能已经。。。②本来能够却没做，差点就

He can’t [couldn’t] have seen her there. 他不可能在那儿见到她。

He could have gone home. 他可能已回家了

He could have told her, but he didn’t choose to. 他本来可以告诉她的，但他却没有。

Be able to

1.    表示能力，相比can，有更多的时态，但是be able to后面的动词一般不用被动语态，can则可以。

I’m sorry I haven’t been able to answer your letter in time.

The desk can’t be moved.

2.    过去时中， be able to可以用来表示通过努力终于做成了某事，相当于managed to do，而could不能

I talked with her for a long time, and eventually I was able to make her believe me.

B. may 和 might

1.表示允许﹑许可，might提问更委婉。语气can, could, may, might由强到弱

 ---May/Might I watch TV after supper?

    ---Yes, you may./ Yes, please./ Certainly.

 ---No, you mustn't. / No, you may not. / No, you can’t./No, you’d better not.

2. 表示推测，有“或许”、“可能”的意思。might把握更小。疑问句用can/ could.

He may/might be right./  I hear there may be a few copies left.

He may/might come today (tomorrow).

3. may表示祝愿，倒装。May +主语+动词原形。May you succeed!/May you all be happy.

☆may [might] as well…意为“不妨”、“还是…为好”等，用 might 比用 may 语气更委婉。

I’m ready，so I might as well go now．我已准备好，因此不妨现在就走。

  There’s nothing to do, so I may [might] as well go to bed.

C. must, have to    

1. 二者表示“必须”，但must无时态变化，多表主观意志，have to有时态变化，多表客观需要。must否定式mustn’t表示“不可以”、“不准”、“禁止”等。Have to的否定式don’t have to相当于needn’t，意思为“不必”。

Everybody must obey the rules../You mustn’t lend it to others./You mustn’t speak like that to your mother.

It’s getting dark. I have to go home now.

☆在回答有“must” 的询问时，肯定回答要用must，否定回答要用needn’t或don’t have to，意思是“不必”

--- Must I leave now?      --- Yes, you must. 

  ---No, you needn’t. / No, you don’t have to.

2. must表示推测（“一定”、“必定”），表肯定的推测, 其否定的推测用can’t，表示“不可能” 。

You must be hungry after the long walk. / It can't be Jim, for he has gone to Beijing.

The Chinese language must have the large number of speakers.

3．must  表示说话人不耐烦的态度，“干嘛偏要”Must you talk in that way？

☆ must + have + done，表示对过去事物的肯定推测。 “一定做过...”

 He must have told my parents about it.  他一定把这件事情告诉我父母亲了。

☆ must表示推测时，其反意疑问句应根据动词的实际时态而变化。如：

It must be nice to take a walk here, isn’t it?

Tom buys a lot of apples ,he must like eating them, doesn't he？

Must have done 的反意疑问句有三种情况:

①
从句中含有过去的时间状语,反意疑问句用过去时.

The ground is wet , it must have rained last night, didn’t it?

②
从句中含有过去完成时的时间状语,反意疑问句用过去完成时.

By the end of last term, we must have learnt 20## words, hadn’t we?

③
若从句中不含任何时间状语,反意疑问句用现在完成时

We must have been met somewhere (before), haven’t we?

☆must 表示“必须”　“有必要”时，反义疑问句部分用mustn’t...? 或 needn’t ...?　

   You must go home right now, needn’t you?

☆must 用否定形式 mustn’t时，附加疑问句部分用may或must…?

You mustn’t cheat in the examination, must you?

3. 表示与说话人愿望相反及不耐烦．意为“偏要”．

-____you make so much noise? 

-Sorry, I will take care not to.       A  Must    B Can   C May   D Would

D. ought to/ should/ shall

Ought to 

ought to用于反映客观情况或涉及义务和规定时，常译作“应该”、“应当”(和should差不多， 只是语气较强)，有时表示非常可能的事情。

There ought not to be much noise in a hospital.

--- Ought he to go?    --- Yes, he ought to.

 If she is completely well, she ought to be back at school today.

ought to have done指过去动作,表示一件事情该做而未做。

ought not to have done 表示一件不该做的事情却做了。

should

1.用于表示义务和职责，“应该”．表示自己的主观看法,语气比ought to弱。

   You should do your homework now.

2.表推测，“按道理，按常理应该”

☆ should + have done 指过去动作,表示一件事情该做而未做。

They should have arrived by two o’ clock.

3.表示惊讶,赞叹，不满，责备 “竟然”

I am sorry that you should do such a thing.

4. 用于if引导的虚拟条件句中，表示一件事听起来可能性小，但也不是完全不可能。有“万一”的意思

Should I be free tomorrow, I’ll come.

Ask Tom to ring me up if you should see him.

5.作为shall的过去式， 用于第一、第三人称作主语的疑问句或间接引语中，用来征询对方意见。

Mr. Smith asked if he should return the books on time.

shall

1. 用于第一、第三人称, 在疑问句中，shall 用来征询对方意见。“……好吗？”“要不要……？”

Where shall I wait for you?/ Shall he come at once?/ Shall we start the meeting now?

2. shall 作为情态动词，用于第二、第三人称，陈述句，表示说话人的意愿，有“命令”、“警告”、“威胁”、“强制”、“允诺”等意思。“必须，应，可以”．

You shall do as I say. （命令）

Tell him that he shall have the book tomorrow. （允诺）

You shall be punished if you break the law. (表警告)

3. 用于第三人称的陈述句中，表示条约﹑规定﹑法令等文件中的义务或规定

  The National Party Congress Shall be held every five years.

E. will 和 would

1.  表示“意志”、”决心” 、“意愿”，可用于多种人称。will 指现在，would 指过去。

I will tell you all about it./  He won’t go.

2. 表示询问对方的意愿或向对方提出请求,在疑问句中用语第二人称时，委婉语气用would.

I’m going to go shopping after school. Will you go with me?

Will/would you please give him a message when you see him?

3.  表示习惯动作，有“总是”、“惯于”的意思。过去式would

He’ll talk for hours if you give him the chance.

☆ Would表示过去经常发生的动作，不表示过去存在的状态。Used to既可以表示过去的经常发生的动作，又可以表示过去存在的状态。

4.  表示功能，“能”

    The door won’t open. / The car won’t start.

5.    will用于叙述真理,客观规律时“会”

    Oil will float on water. / Fish will die without water.

F. need 和 dare

1.  need 表示“需要”、“必须”，没有人称和时态的变化。通常用在否定句或疑问句中。疑问句的肯定回答用must。

He needn’t pay for it.

 --- Need you go now?        --- Yes, I must.  --- No, I needn’t.

☆ “needn‘t + have done” 表示过去做了没必要做的事情。

   You needn't have taken it seriously.  这件事情你不必太认真。

2. dare 作情态动词表示“敢”，其过去式为dared，无人称变化。通常用于否定句、疑问句、条件从句和if/whether 引出的宾语从句中。

How dare you say I’m unfair?

She dare not do so.

He asked me if I dared speak English in public.

☆ need 和 dare 也可用作行为动词，变化与一般动词相同

注意：dare作行为动词时，肯定句中要接带to的不定式，而在否定句、疑问句、条件从句不定式的to可带也可不带。而need作行为动词时，后面都要接带to的不定式。

She didn’t need to go.

 --- Who dares to go?     - -- I don’t dare (to) go.

☆ I dare say …作插入语,我想, 大概, 可能, 或许，这个短语不要to

G. had better “最好”

— We had better go now.

— Yes, we had (we'd better / we had better).

Hadn't we better stop now? (Had we better not stop now?)

I think I'd better be going. （用于进行时态，表“最好立即”）

You had better have done that. （用于完成时态，表未完成动作）

Ⅵ情态动词+ have done

1、must have done,“一定做过/一定已经．．．”，表示对过去情况极大把握地推测，仅用于肯定句

2、may/might have done 也许做过某事（推测）；本来可以做某事却没做

3、can't have done 为否定句或疑问句,对过去的推测“不可能，一定没做过某事”

   could have done本来可以做某事却没做

4. needn’t have done 表示”不必要做某事，但做了”，而needn’t do 则表示”不必做(也没做)”

5.、ought to /should have done 表示”本来应当做的却没做”

    oughtn’t / shouldn’t have done 本来不应该做某事却做了

6、would/could/might/should + have done 用来表示与过去事实相反的虚拟语气

7、would rather have done 表示”当时宁愿做了某事”，否定形式：would rather not have done

e.g. If I had been free that day, I would have gone with you.

8、would like/love to have done 表示” 本想做某事” 而实际上未做。

 

第二篇：情态动词用法总结

情态动词：不能单独作谓语

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1. must、have/has to的用法

? have/ has to强调客观需要,意为 “必须,不得不”;must用于表示主观看法，意为“必须，应该”

? Must you come here for class or do you have to?

? ★ 以must开头的疑问句，肯定回答用must,否定回答用needn’t或don’t have to ? ---Must I finish the homework today?

? ---Yes, you must.

? ---No, you don’t have to/needn’t.

? must not (mustn’t)表示禁止

? No parking.

? You must not (mustn’t) park here.

I’m sorry. I ___ go now. My father told me on the phone that my mother was ill. (05厦门）

A. can B. may C. have to D. think

2. need的用法

? need to do实义动词，need do情态动词,意为“需要”

? The sheep need to fight with the wolves.

? (The sheep don’t need to fight with the wolves.)

? The sheep need fight with the wolves.

? (The sheep need not fight with the wolves.)

? ★ 用need提问，肯定回答用must, 否定回答用needn’t

? ---Need I return home by ten?

? ---Yes, you must.

? ---No, you needn’t.

“Where’s my umbrella?” “It’s fine today. You ___ take an umbrella with you.”（06新疆）

A. can’t B. needn’t C. mustn’t D. shouldn't 只作情态动词：must, can, could, may, might 既作情态动词也作实义动词：need 既作情态动词也作助动词：will, would, shall, should 具有情态动词的某些特征：have to, ought to, had better 情态动词的特征 有一定的词义，但不能单独作谓语，必须和实义动词或系动词连用，构成谓语 无人称和数的变化（除have to) The little girl has to sell matches. 后接动词原形 The little girl has to sell matches. 具有助动词的作用，可用于构成否定句、疑问句及简明回答 ---Can you play ping-pong? ---Yes, I can./ No, I can’t.

---I don’t mind telling you what I know.

---You __. I’m not asking you for it.（06济南）

A. needn’t B. mustn’t C. may not D. can’t

3. can、could的用法

? 表示能力，意为“能，会”

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? Can you play badminton? 表示请求或允许，多用于口语中，意为“可以”，相当于may，can的语气强于could You can go now. Could you give me a hand? 以can、could开头的问句，肯定、否定回答仍用can、could

? ---Could she swim when she was a child?

? ---Yes, she could./No, she couldn't.

We hope that as many people as possible ___ join us for the charity show tomorrow.（08苏州）

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

---___ you friend play the guitar?

---Yes, he can, but he can’t play it well.（06广西）

A. Must B. Can C. Should D. Need

4. may、might的用法

? 表示请求、许可，意为“可以”，may的语气强于might

? May I borrow your book?

? I asked her if I might leave.

? ★ may表示请求时，主语为第一人称的一般疑问句，肯定回答用may,其否定回答

用mustn’t,表示“不许，禁止”

? ---May I go now?

? ---Yes, you may.

? ---No, you mustn’t.

---Is Mr. Brown driving here?

---I’m not sure. He ____ come by train.（08安徽）

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

---May I put my bike here?

---No, you ___. You should put it over there.（04北京）

A. couldn’t B. needn’t

C. mustn’t D. won’t

5. will、would、shall、should (ought to)的用法

? shall用于第一人称表示征求意见询问

? Shall we have dinner at that restaurant?

? should、ought to表示义务、责任，“应该”

? We should/ought to obey our parents.

? We shouldn’t/ought not to sleep in class.

We ___ keep the new traffic law and learn how to protect ourselves.（08湖北）

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

6. will、would用于第二人称表示征求意见询问，也可表达现在的意愿,will的语气强于would

? Will you pass me the book?

? I would do anything for you.

? would表示过去习惯性的动作，相当于used to

? I would go to the gym every week during my college years.

= I used to go to the gym every week during my college years.

7. had better的用法

? 表示最好做某事 ，否定为had better not

? You’d better ask him to stop laughing.

? He’d better not laugh any more.

The baby is too young. You ___ give her big pieces of food.（08沈阳）

A. may B. must C. may not D. must not

Tony ___ go to the opera on Saturday because he’s going to have a meeting.（08天津）

A. can’t B. might C. mustn’t D. should

---Tom, don’t drive too fast, you ___ hit the others’ cars.

---Ok, I won’t, Mum.（04乌鲁木齐）

A. must B. need C. may D. have to

---Must I do the work now?

---No, you ____. You may do it later.（07四川）

A. can’t B. mustn’t C. needn’t D. shouldn’t

表推测的情态动词的用法

对现在或将来的行为的推测(情态动词+动词原形）

? must表示“肯定”推测，只用于肯定句

Xi Yangyang must be a boy.

? can, could, may, might用于肯定句中，表示“可能”推测,语气由强到弱

The dictionary may be there.

It might rain this evening.

I’m sure this book ___ Li Lei’s, because there is his name on it.（08吉林）

A. can’t be B. may be

C. might be D. must be

? can, could, may, might用于否定句中，can’t, couldn’t 表示“不可能”，may not,

might not表示“可能不”，

He can’t be there.

The news may not be true.

? 表推测的把握性程度由低到高为might →may →could →can →should →ought to

→would →will →must

---Listen! Is Professor Bloom giving a speech in class?

---No, it ___ be him. He has gone to France.（08潍坊）

A. may not B. mustn’t

C. needn’t D. can’t

---Who’s that boy reading in the garden? Is that David?

---It ___ be David. I saw him in the classroom just now.（08重庆）

A. must B. can’t C. may D. shouldn’t

---Will you answer the telephone? It ___ be your mother.

---Sorry. I ____. I’m busy.（08山东）

A. can; mustn’t B. will; can’t

C. may; can’t D. need; will

Four hundred dollars for a pair of shoes, you ___ be joking!（08杭州）

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