情態(tài)動(dòng)詞本身有一定的詞義，表示語氣的單詞，不能獨(dú)立作謂語。情態(tài)動(dòng)詞主要有can (could), may (might), must, need, ought to, dare(dared), shall(should), will (would)must。

1英語情態(tài)動(dòng)詞用法順口溜

情態(tài)動(dòng)詞要記牢;動(dòng)詞原形來跟梢。

不管人稱單復(fù)數(shù);現(xiàn)在過去樂逍遙。

can表能力和許可;也許可能may來表;

必須一定must;should應(yīng)該來報(bào)到。

英語情態(tài)動(dòng)詞用法順口溜

回答不須needn’t;mustn’t為不必要。

否定只要接not;疑問趕緊往前跑。

2英語情態(tài)動(dòng)詞用法有哪些

can (could),may (might）的用法

can (could) 表示說話人能，可以，同意，準(zhǔn)許，以及客觀條件許可，could 為 can 的過去式。

Can you pass me the books?你能給我遞一下書嗎？

Could you help me,please?請問，你能幫助我嗎?

What can you do?你能干點(diǎn)什么呢?

Can you be sure?你有把握嗎?

can 和could 只能用于現(xiàn)在式和過去式兩種時(shí)態(tài)，將來時(shí)態(tài)用 be able to 來表示。

He could help us at all.他完全可以幫助我們。

With the teacher's help,I shall be able to speak English correctly.由于老師的幫助，我將能準(zhǔn)確地講英語。

may (might) 可以，表示說話人同意，許可或請求對方許可。

You may take the book home.你可以把書帶回家去.

May I come in?我可以進(jìn)來嗎?

May I use your dictionary?我可以用你的詞典嗎?

You may put on more clothes.你可以多穿點(diǎn)衣服.

He said he might lend us some money.他說他可以借給我們一些錢。

may 否定式為 may not，縮寫形式是 mayn't.

might 是may 的過去式，有兩種用法，一種表示過去式，一種表示虛擬語氣，使語氣更加委婉，客氣或?qū)赡苄缘膽岩伞?/p>

He told me he might be here on time.他說他能按時(shí)間來。

Might I borrow some money now.我可以借點(diǎn)錢嗎?

He might be alive.他可能還活著。

must,need,ought to,dare (dared）用法

Must 必須，應(yīng)該，一定，準(zhǔn)是，表示說話人認(rèn)為有必要做某事，命令，要求別人做某事以及對事物的推測。

must 用來指一般現(xiàn)在時(shí)和一般將來時(shí)，過去式可用 have to 的過去式代替。

I must finish my work today. 我今天必須完成我的工作。

You mustn't work all the time. 你不能老是工作。

Must I return the book tomorrow? 我必須明天還書嗎?

After such a long walk,you must be tired. 走了這么長的路，你一定困了。

He must be the man I am looking for. 他一定是我要找的人。

He had to go because of somebody's calling him that day. 那天他要走是因?yàn)橛腥私兴?/p>

must + have + 過去分詞，表示現(xiàn)在對過去事物的推測。

He must have told my parents about it.他一定把這件事情告訴我父母親了。

He must have received my letter now.他現(xiàn)在一定收到我的信了。

It's six o'clock already,we must have been late again.已經(jīng)六點(diǎn)鐘了，我們一定又遲到了。

must 和 have to 的區(qū)別：must 表示說話人的主觀思想，have to 表示客觀需要。

You must do it now.你必需現(xiàn)在就干。（說話人認(rèn)為必須現(xiàn)在干）

I have to go now.我得走了。（客觀條件必須現(xiàn)在走）

need 需要 多用在否定式或疑問句中.

Need I attend the meeting tomorrow?我需要明天參加會(huì)議嗎?

You need not hand in the paper this week.這一周你不必交論文。

need 是一個(gè)情態(tài)動(dòng)詞，用法完全和其他情態(tài)動(dòng)詞一樣，但 need 還可當(dāng)作實(shí)義動(dòng)詞使用，這時(shí) need 就象其他動(dòng)詞一樣，有第三人稱，單復(fù)數(shù)，后面加帶 to 的動(dòng)詞等特性。

I need a bike to go to school.我上學(xué)需要一輛自行車。

Do you need a dictionary?你需要詞典嗎?

She needs a necklace.她需要一條項(xiàng)鏈。

needn't + have + 過去分詞 表示過去做了沒必要做的事情。

You needn't have taken it seriously.這件事情你不必太認(rèn)真。

dare 敢, 多用在否定或疑問句中。

The little girl dare not speak in public.小女孩不敢在公眾面前說話。

Dare you catch the little cat?你敢抓小貓嗎?

dare 除用作情態(tài)動(dòng)詞外，更多的是當(dāng)實(shí)義動(dòng)詞使用，用法同實(shí)義動(dòng)詞一樣，要考慮人稱，單復(fù)數(shù)，時(shí)態(tài)等。

Do you dare to walk in the dark?你敢黑夜走路嗎？

He doesn't dare to tell the teacher what happened that day.他不敢告訴老師那天發(fā)生的事。

have to,ought ，will ，Shall,should . ought 應(yīng)當(dāng)，應(yīng)該 后面跟帶有 to 的動(dòng)詞不定式。

You ought to read these books if you want to know how to repair the motorcar.如果你想知道如何修理汽車，你應(yīng)該讀這些書。

You ought to bring the child here.你應(yīng)該把孩子帶來。

ought + to have done 句型。指過去動(dòng)作，表示一件事情該做而未做。

You ought to have been here yesterday.你昨天就應(yīng)該來。

ought not to have done 句型。表示一件不該做的事情卻做了。

You ought not to have taken the book out of the reading-room.你不應(yīng)該把書帶出閱覽室。

will (would）決心，愿望。would 為 will 的過去式，

可用于各人稱。

I'll do my best to catch up with them.我要盡全力趕上他們。

I'll never do it again,that's the last time.我再不會(huì)做那件事情了，這是最后一次。

He said he would help me.他說他會(huì)幫助我。

will,would用于疑問句表示說話人向?qū)Ψ教岢稣埱蠡蛟儐枺?would 比 will 更婉轉(zhuǎn)，客氣。

It's hot. Will you open the windows?天氣太熱了，你能打開窗戶嗎?

Will you help me to work it out?你能幫我解這道題嗎?

Would you like some coffee？給你來點(diǎn)咖啡怎樣？

Shall,should表示命令，警告，允諾，征求，勸告，建議驚奇。

You should hand in the exercise book.你應(yīng)該交作業(yè)本了。

This should be no problem.這應(yīng)該沒問題。

Shall we go now.我們現(xiàn)在可以走了嗎?

Why should I meet him？為什么我要見他?

Shall的用法：

Shall用于第一人稱，表示征求對方的意愿。如：

What shall we do this evening?

Shall用于第一、第三人稱疑問句中，表示說話人征求對方的意見或向?qū)Ψ秸埵尽Ｈ纾?/p>

Shall we begin our lesson?

When shall he be able to leave the hospital?

Shall用于第二、第三人稱，表示說話人給對方命令、警告、允諾或威脅。如：

You shall fail if you don't work harder. （警告）

He shall have the book when I finish reading. （允諾）

He shall be punished. （威脅）

Should的用法：

1． Should表示義務(wù)、責(zé)任、勸告、建議，其同義詞是ought to；在疑問句中，通常用should代替ought to。如：

You should go to class right away.

Should I open the window?

Should的含義較多，用法較活，現(xiàn)介紹三種其特殊用法。請看下面的句子：

① I should think it would be better to try it again. 我倒是認(rèn)為最好再試一試。

② You are mistaken,I should say. 依我看，你是搞錯(cuò)了。

③ I should advise you not to do that. 我倒是勸你別這樣做。

④ This is something I should have liked to ask you. 這是我本來想問你的。

從以上例句可以看出：情態(tài)動(dòng)詞should用于第一人稱時(shí)可以表示說話人的一種謙遜、客氣、委婉的語氣。

Should還可以用在if引導(dǎo)的條件從句，表示一件事聽起來可能性很小，但也不是完全沒有可能。相當(dāng)于“萬一”的意思。從句謂語由should加動(dòng)詞原形構(gòu)成，主句謂語卻不一定用虛擬語氣。如：

⑤ Ask her to ring me up if you should see her. 你萬一見到她，請讓她給我打個(gè)電話。

⑥ If you should change your mind,please let us know. 萬一你改變主意，請通知我們。

⑦ Should I (If I should) be free tomorrow I will come. 萬一我明天有時(shí)間，我就來。

此外，Why(or How) + should結(jié)構(gòu)表示說話人對某事不能理解，感到意外、驚異等意思。意為“竟會(huì)”。如：

⑧ Why should you be so late today? 你幾天怎么來得這么晚？

⑨ — Where is Betty living? — 貝蒂住在哪里？

— How should I know? — 我怎么會(huì)知道呢？

⑩ I don't know why you should think that I did it. 我真不知道你憑什么認(rèn)為這件事是我干的。

2． “should + have + 過去分詞”結(jié)構(gòu)一般表示義務(wù)，表示應(yīng)該做到而實(shí)際上沒有做到，并包含一種埋怨、責(zé)備的口氣。如：She should have finished it.

I should have helped her,but I never could.

You should have started earlier.

3.表示規(guī)章制度，用should

will和would

1． 表示請求、建議等，would比will委婉客氣。如：

Would you pass me the book?

2． 表示意志、愿望和決心。如：

I will never do that again.

They asked if we would do that again.

3． 用“will be”和“will(would) + have + 過去分詞”的結(jié)構(gòu)表示推測，主要用于第二、三人稱。前者表示對目前情況的推測，后者表示對已經(jīng)完成的動(dòng)作或事態(tài)的推測。如：

This will be the book you want.

He will have arrived by now.

The guests would have arrived by that time.

I thought you would have finished this by now.

4．will表示習(xí)慣、請求，固有性質(zhì)等。

Everyday he will sit here hour after hour doing nothing.（習(xí)慣）

Will you help me with my English?（請求）

The door won't open. （固有性質(zhì)）

5．Would可表示過去反復(fù)發(fā)生的動(dòng)作或某種傾向。Would表過去習(xí)慣時(shí)比used to正式，并沒有“現(xiàn)已無此習(xí)慣”的含義。如：

The wound would not heal.

During the vacation he would visit me every week。

6． 表料想或猜想。如：

It would be about ten when he left home.

What would she be doing there?

I thought he would have told you all about it.

ought to

1．Ought to表示應(yīng)該。如：

You ought to take care of him.

2．表示推測。注意與must表示推測時(shí)的區(qū)別：

He must be at home by now. （斷定他已到家）

He ought to be home by now. （不十分肯定）

This is where the oil must be. （比較直率）

This is where the oil ought to be. （比較含蓄）

3．“ought to + have + 過去分詞”表示過去應(yīng)做某事而實(shí)際未做。如：

You ought to have asked him (but you didn't).

這時(shí)，ought to和should可以互相換用。

注意：在美國英語中，ought to用于否定句和疑問句時(shí)，to可以省略。如：

Ought you smoke so much?

You oughtn't smoke so much.

ought和should的區(qū)別：

1．ought語氣略強(qiáng)。

2．should較常用。

3.ought在美國英語中用的很少，而should卻相當(dāng)常用。

4．ought屬正式用語。

注：由于ought to 沒有過去式，所以在直接引語變間接引語的過程中，就不再變化.