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助动词定义分类be类助动词have类助动词will类助动词do类助动词情态动词定义分类常见情态动词情态动词用法要点情态动词用法表示征求对方意见或许可表示邀请或请求表示允许或许可表示禁止表示建议或劝告表示能力表示推测表示轻微埋怨、责备或后悔表示警告、允诺、命令或威胁表示偏执表示怀疑表示习惯性情态动词用法区别

助动词

定义

协助主要动词构成谓语的词叫助动词，也叫辅助动词。被协助的动词被称作主要动词。助动词用来构成时态和语态。助动词具有语法意义，但没有词汇意义，不可单独作谓语。

分类

be类助动词

be类助动词：be, am, is, are, was, were, been, being。这类助动词与现在分词构成进行时态，与过去分词构成被动语态。例如：

Theywere watchingTV when we got there.（构成过去进行时）

【翻译】当我们到那儿时他们正在看电视。

Weare doingour lessons now.（构成现在进行时）

【翻译】我们正在做功课。

The projectwas finishedlast month.（构成被动语态）

【翻译】工程上个月已完工了。

The treesare beingplanted now.（构成被动语态）

【翻译】人们正在植树。

have类助动词

have类助动词：have, has, had, having。这类助动词与过去分词构成完成时态。

My unclehas comeback home.（构成现在完成时）

【翻译】我叔叔已到家了。

Theyhaven’t finishedtheir match yet.（构成现在完成时）

【翻译】他们还没有结束比赛。

Before we went home, wehad hada little rest.（构成过去完成时）

【翻译】在回家之前我们休息了一会。

Having donethe work, we had a bath.（构成现在分词的完成时）

【翻译】干完活后，我们洗了个澡。

补充说明

have done 和 have been done 都表示的是现在完成时，having done 和 having been done 都是动词ing 的完成形式，在句子中作状语，起到补充说明的作用。

这里要注意的是，having 所接的动词发生的时间在主句中谓语动词发生的时间之前。比如：Having driven all day,we were so tired. 这个例子中，having driven表示“我们”的状态，“开了一天的车”，并且，drive 的动作发生在 be tired的之前。了解了上面的概念，再来解释having done 和 having been done的区别，前者having done表示的是主动，后者having been done表示的是被动。例：

1、Having driven all day,we were so tired.

【翻译】我们开了一天的车，现在都很累了。

having driven表示的是主动，是“我们开了一天的车”

2、Having been criticized today, he was so sad.

【翻译】今天被批评了，他很难过。

是"he"被批评，而这个原因状语又是修饰"he"，所以要用被动，have been done。还有一种情况，having been doing，理解了之前两种用法，那么也会很清楚，这个用法也是动词ing的完成进行时，表主动。

will类助动词

will类助动词：will, would, shall, should。这类助动词与行为动词原形连用构成将来时。例如：

Shewill inviteher good friends to her new house.（构成一般将来时）

【翻译】她将邀请她的好朋友到她的新房子里。

He said that hewould goshopping tomorrow if possible.（构成过去将来时）

【翻译】他说如果可能的话他明天将会去购物。

do类助动词

do类助动词：do， does， did。这类助动词与其它行为动词一起构成否定句和疑问句。例如：

Do you enjoy living in China?（构成一般疑问句）

【翻译】你喜欢住在中国吗？

Does your sister like playing computer games?（构成一般疑问句）

【翻译】你的姐姐喜欢打电子游戏吗？

He didn’t watch TV last night.（构成否定句）

【翻译】他昨天晚上没看电视。

I don’t get up early in the morning.（构成否定句）

【翻译】我早上起床不早。

情态动词

定义

情态动词本身有词义，但不能独立构成谓语，用来表明特定的感情和态度。情态动词没有人称和数的变化，其后必须跟动词原型。

分类

只做情态动词：can, could, may, might, must, had better, be able to

可做情态动词又可做实义动词：need, dare

具有情态动词特征：have(has, had) to, used to, ought to

可做情态动词又可作助动词：shall(should),will(would)

常见情态动词

情态动词用法要点

动词原型跟后面，说话语气较委婉

can 表 “能力”

may 表 “许可”

must 表 “责任”或“义务”，否定回答needn’t换

need 表 “需要”

dare 表 “敢”

should 表 “应该”

would 表 “愿”

have to 表 “被迫”，表客观。对must构成的一般疑问句作否定回答只能用needn’tdare和need一般在疑问句或否定句中才算情态动词，而肯定句中作行为动词。

情态动词用法

表示征求对方意见或许可

情态动词：must, can, could, may, might, shall。例如

Must I hand in my homework today?

Yes, you must.\Yes, you have to.

No, you needn’t.\No, you don’t have to.

Can I come in and have a good look at your house with my girlfriend now?（比较口语化）

Could I use your mobile phone as mine is power off?（语气委婉）

Yes, you can.（回答不能用could）

May \ Might I use your bicycle?（比较正式，用might语气更委婉）

Shall I open the window to let in some fresh air?（shall此用法只用于第一和第三人称）

Shall he come to sit in this seat and listen to your speech?（同上）

表示邀请或请求

情态动词：can, will, would, could, 一般用于第二人称;用would和could表示语气更加委婉。如

Can \ Could you lend me some money to buy some books and dictionaries?

Will \ Would you please tell us a story or joke for pleasure?

表示允许或许可

情态动词：can, may。如：

You can sit here and do your homework because the seat is not occupied.

You may go to bed and get up as late as you like; nobody cares about that.

表示禁止

情态动词：can’t, mustn’t, shan’t, shan’t多表按照某规定“不能”。如

They can’t wear whatever they like when they are at school.

Anybody mustn’t take books out of the library without permission.

You shan’t hand in your papers ahead of time in the examinations according to the regulations.

表示建议或劝告

情态动词：ought to, should, had better, need。如

Parents ought to take care of their children when they are young and children ought to look after their parents when they are old.（ought to表示义务，为别人做某事）

You should do a lot of exercise regularly to improve your health.（should表建议，多指为自己做某事）

You had better put more clothes in case it is cold on the mountain.（多用于上级对下级，长辈对晚辈之间）

In order to learn English well, you need practice speaking English more often besides reading.（比较口语化）

表示能力

情态动词：can, could, be able to，can表示现在的能力，could表示过去的能力，be able to用来填充can，could没有的时态，但was\were able to除了表示过去的能力以外还表示“过去设法做成某事”，等于managed to do something或succeeded in doing something 。如

When I was in China I couldn’t speak English, but now in USA I can speak it fluently.

I am sure that this promising young man will be able to support his family in the future.

They charged 20 thousand dollars for the car but I was able to bring the price down.（managed to\succeeded in）

表示推测

情态动词：may, might, must, can, could, should, ought to，must表推测语气最强，但只用于肯定句，否定式中用can’t或couldn’t代替;must\may\might\can’t\could\couldn’t\couldn’t + have done表示对过去发生事情的推测;should，ought to表示"按理说应该"。如

It may be the headmaster’s office. I am not sure.（把握性不大）

He was careless, He might have won the first place otherwise.（过去的可能性很小）

Who can it be?（can 代替 must）

It must be our manager.

No, It can’t be him. He is in Japan at the moment.（must 不能用于否定句，由can’t代替）

Was it in the street that he played football yesterday?

It could be in the street, but I am not sure.（可能性不大）

There were five men in your car during the long journey. It must have been uncomfortable.（= It couldn’t have been comfortable.可能性很大）

He was with me in the class at that time yesterday. He couldn’t have played basketball on the playground yesterday.（动词是过去式时用couldn’t have done，不用can’t have done）

He should be over fifteen years old, because he is a student in the 11th grade.

She ought to turn up at any moment, for she is always on time for work.

表示轻微埋怨、责备或后悔

情态动词：should\ought to\needn’t\could\might + have done，如

The movie star has died. You should \ ought to have come here earlier.（过去该做而没做）

She is unhappy now. I shouldn’t \ oughtn’t to have told her the bad news.（过去不该做而做了）

I needn’t have carried so much cash. All my bank cards could be available actually.（做了没必要做的事）

You could have married me at that time. I loved and love you but he doesn’t.（过去本可以做但没做）

She was out of mind. She might have passed the exam otherwise.（过去也许会但没有）

表示警告、允诺、命令或威胁

情态动词：shall，常用于第二、三人称，如

You shall take the book to read as long as I finish it before Friday.

All the candidates shall remain at their seats until the bell rings announcing the end of the exam.

表示偏执

情态动词：must，如

If you must want to know my age, which is a privacy, let me tell you unwillingly.

Must you smoke at a no-smoking area? You will be punished seriously.

表示怀疑

情态动词：should（竟然）, dare, can’t，如

Such a high official should be so rude to that little girl. What a shame!

How dare you say that I treated you unfairly? Actually I did it right.

Why can’t you know my telephone number and email address? We are good friends.

表示习惯性

情态动词：will，would，will表示现在反复，would表示过去反复，如

After work he will go to the cafe to have a cup of coffee every day.

Whenever and wherever he met him, he would stop the soldier and ask the same questions again and again in the army.

情态动词用法区别

must & have to。must表示主观上“必须”，have to表示客观逼迫“不得不”，如

We must study English very hard, which I like very much.

I have to study English very hard, because I have to pass the exam in the next.would, used to, be used to doing & be used to do something。would表示过去反复的动作，而used to则侧重“过去如此，现在已经不是那样了”以及“过去存在的状态”;be used to doing是表示“习惯于做某事”，其中be有时态和人称的变化，后跟动名词;be used to do something表示“某东西被用来做某事”，如

When he was in that factory, he would go to that coffee shop at the corner after work every day.

He used to smoke and drink a lot, but now he doesn’t.

There used to be a big temple where there is a school now.（过去的状态）

He has been used to working in such bad conditions.

Wood can be used to make desks and chairs as well houses.didn’t need to do & needn’t have done。didn’t need to do表示“过去没必要做也没做”，而needn’t have done表示“过去没必要做但已经做了”，如

It was raining yesterday, I didn’t need to work in the fields, so I stayed at home.（没去工作）

It was Sunday yesterday, I needn’t have gone to school. But I forgot it and went as usual.（去学校了）need & dare。这两个词既可用作情态动词，又可用作实义动词，一般来说，情态动词多用于否定和疑问句;实义动词用于各种句式，后跟动词不定式，I dare say是固定短语，意为“ 我认为、我相信”，如

Need I finish my report by six o’clock today?（情态动词）

Yes, you must \ you have to.

No, you needn’t \ you don’t have to.

As a Chinese high school student, I need to work at lest 10 hours a day.（实义动词）

My cat need repairing \ to be repaired thoroughly.（实义动词，后跟动名词主动表被动）

Tom darn’t go out alone when it is dark at night.（情态动词）

Dare you go home to face your parents when you haven’t done well in the exam?（情态动词）

I don’t dare to feel the snake even if it is dead.（实义动词）can’t have done & couldn’t have done \ could have done。can’t have done 和 couldn’t have done均可表示must的否定推测，强调从现在角度出发推测过去某事“不可能”;但当主句的谓语动词是过去式时，就必须用couldn’t have done;could have done表示“过去有能力或有可能做某事但没有做”，有惋惜、遗憾、批评、责备等意思，如

His jacket is till here, so he can’t(couldn’t) have gone home.（must的否定式）

My sister met him at the Grand theatre yesterday, so he couldn’t have attended your lecture.（过去不可能）

You could have walked here instead of taking a taxi; it is so near.would like to do & would like to have done。would like to do表示现在或将来“想做某事”，而would like to have done表示过去“想做某事但没做成”。如

I would like to go to the concert tonight, but my parents don’t allow me to.

I would like to have gone to the concert last night but I had to review lessons for the exams.

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