英语助动词和情态动词及练习

英语助动词和情态动词及练习
英语助动词和情态动词及练习
⼀、概述
不同的时态（⼀般式、进形式、完成式、将来式），不同的语态（主动、被动），不同的语⽓（祈使、陈述、虚拟），不同的结构（肯定、否定、疑问），以及说话者本⾝的态度或命令、请求、愿望、可能等，所有这些都要借助于助动词和情态动词表达出来。

助动词⼀般没有词意，不能单独作谓语动词，除⾮省略句中。

他们只参加时态、语态、语⽓或否定、疑问结构。

情态动词有词义，可以⽤来表⽰说话者的语⽓和态度。

主要的助动词和情态动词如下表：
⼆、助动词
助动词⼀般没有词意，不能单独作谓语动词。

其作⽤在于帮助构成各种时态、语态、否定、疑问等。

1、助动词be（am, is, are, was, were, being, been）的⽤法
（1） be后跟现在分词构成进⾏时态。

Who is playing the violin?谁在拉⼩提琴？
She was reading a book then.那时她正在读书。

（2）be后跟过去分词构成被动语态。

He was asked to do the work.有⼈要他⼲这件⼯作。

You are invited to attend the meetintg.有⼈邀请你参加会议。

（3）be 后跟不定式作谓语，有如下⼏种情况：
①表⽰计划、安排将要发⽣的事。

Who are we to meet?我们要见谁呀？
I'm to have supper with John this afternoon.今天下午我要与约翰⼀起吃晚饭。

②表⽰指⽰、命令，否定式表禁⽌。

You are to see the headmaster today.今天你必须去见校长。

You are not to enter the room without permission.未经允许你不能进⼊房间。

③表⽰义务、责任等，同should。

You are to be back before 5.你得在5点钟以前回来。

What is to be done?该⼲什么。

④表⽰可能性，与情态动词may, can同义。

Such books are to be found in any library.这种书任何图书馆都有。

Not a sound was to be heard.⼀点声响也没有。

⑤表⽰后来发⽣的事，可以⽤来表⽰命运或注定
They say good-bye, little knowing that they were never to meet again.他们告别了，没想到再也不能相见了。

He was to regret the decision.他有⼀天会后悔做出这⼀决定的。

⑥⽤于习语
Where am I to go? 我该向何处去？
What am I to do? 我该怎么办？
2、助动词have(has, had, having)的⽤法
（1）助动词have可以构成完成时或完成进⾏时
He has been a doctor for 10 years.他当医⽣⼗年了。

This is the place I have been longing to visit.这就是我⼀直渴望参观的地⽅。

（2）和不定式构成谓语，表⽰客观上不得不做的事情。

We've missed the train. We'll have to wait for another one.我们⼰经误了⽕车，我们只能等下⼀列。

-Do we have to start work?我们得⽴刻⼯作吗？
-No. We don't have to.不，不必了。

3、do(does, did) 的⽤法
（1）构成疑问句或否定句
How did you know about it?你是怎样知道这件事的。

He does not smoke. 他不抽烟。

（2）加强语⽓。

He did tell that.他的确告诉了此事。

Do come and see us.⼀定来看我们。

（3）代替前⾯刚出现的动词，避免重复。

-You like popular music, don't you?你喜欢流⾏⾳乐，是吧？
-Yes , I do.是的，我喜欢。

He speaks French as fluently as she does.他讲法语和她讲的⼀样流利。

（4）⽤于倒装句中。

Never did he pay attention to my words.他从不注意我的话。

Only then did I understand the importance of English.只是那时，我才了解到英语的重要性。

（5）构成否定的祈使句。

Don't be so careless.不要那么粗⼼。

Do not hesitate to come for help.只管来求助。

4、shall(should)和will(would) 的⽤法
（1）shall(should)⽤于第⼀⼈称的将来时中，单纯表⽰来
I shall think it over.我要好好考虑⼀下。

When shall I see you again?我何时再见到你？
I rang up to tell her that I should leave for London. 我打电话告诉她我要去伦敦。

（2）will⽤于第⼆、第三⼈称的将来时态中，在现代英语中可以⽤于所有⼈称
He will be 30 next month. 他下⽉将是30岁。

You will have an English test tomorrow.明天你有英语⼩测验。

He wanted to know when you would finish the writing.他想知道你何时完成写作。

三、情态动词
1、情态动词的特征
情态动词表⽰说话⼈对某⼀动作或状态的态度，认为“可能、应当、必要”等等，但本⾝意义不完全，不能单独作谓语，必须和其他动词⼀起构成谓语。

除ought, used, have后跟不定式外，其他情态动词⼀律跟动词原形。

情态动词主要有：can/could, may/might, must, ought to, used to, need, dare, shall/should, will/would, have to等。

2、情态动词的变化形式
（1）没有⼈称和数的变化。

I can /we can/ you can he can/she can/they can/it can
Johnny, you mustn’t play with the knife, you may hurt yourself.约翰，你不能玩⼑，那可能会伤着你。

A left luggage office is a place where bags can be left for a short time, especially at a railway station.⾏李寄存处特别是在⽕车站短时间存放包的地⽅。

He ought to know her address.他该知道她的地址。

（2）⼤部分情态动词有过去式：
can-could may-might need-needed dare-dared shall-should will-would
– Is John coming by train?约翰坐⽕车来吗？
– He should, but he may not. He likes driving his car.应该是，他有可能不乘坐⽕车。

他喜欢开车。

- Are you coming to Jeff's party?你来参加Jeff的聚会吗？
- I'm not sure. I might go to the concert instead. 我不敢肯定，我可能去参加⾳乐会。

（3）少部分情态动词没过去式或者说过去式与原形相同，used to 只有过去式形式。

must-must(had to) ought to -ought to
I used to go there.我(以前)常到那⾥去。

You must be tired after your long journey. 你⾛了这么远的路，⼀定很累。

（4）⼤多数情态动词后⾯还可跟动词的进⾏时、完成时和被动式形式：
can/may/must+ be doing/have done/be done
should/would/might+be doing/have done/be done
He must have earned a large sum of money.他⼀定是挣了⼀笔巨款。

You mustn’t always be talking so much.你不能总是说起来没完没了。

3、否定式和疑问式
情态动词的否定式和疑问式同助动词。

否定式是在情态动词后加not；疑问式是将情态动词提前到主语的前⾯。

-Will you stay for lunch? 你留下来吃午饭好吗？
-Sorry, I can’t. My brother is coming to see me. 对不起，我不能（留下来吃午饭），我兄弟要来看我。

May I ask you a question?我可以问你⼀个问题吗？
I was really anxious about you. You shouldn’t have left home without a word. 你真急死我了。

你不该⼀句话也不说就离开家。

注意：have to 的疑问和否定是借助于do来构成。

Do you have to go out today?今天你得出去吗？
He doesn’t have to go.他没必要去。

四、情态动词的基本⽤法
1、can和could
（1）表能⼒
①意为“能够会”，表⽰体⼒或脑⼒等⽅⾯的能⼒
Some of us can use the computer now , but we couldn't ten years ago.现在我们⼀些⼈能⽤计算机了，但⼗年前我们不能。

Can you ride a bike?你能骑⾃⾏车吗？
What can I do for you?我能为你做点什么？
I could run faster then. 我那时能跑得更快⼀些。

②当can和could表⽰能⼒时，有时可以⽤be able to替换，could表过去，can表现在，有时也可表
将来，但不能与will, shall等助动词连⽤；be able to可以⽤于将来、完成等时态。

She hasn't been able t o come to school for three days.她已经三天没能来上学了。

With his help, we shall be able to build the house.在他的帮助下，我们将能够建造房屋了。

③当我们要强调过去确实使⽤了某种能⼒时，要⽤was（were）able to，⽽不⽤could。

was able to 表
⽰“设法⼲成某事”，即succeed in doing sth.或manage to do sth.⽽could只表⽰“具备某种能⼒”。

He is such a good swimmer that he was able to save the two boys from drowning the other day.
他是⼀位游泳健将，因此前些⽇⼦他救上了两名溺⽔男孩。

The fire spread through the hotel very quickly but everyone was able to get out. 虽然⼤⽕蔓延很快，使旅馆烧起来，但⼤家还是逃了出来。

（2）表可能性
I thought the story could not be true我认为这个故事不可能是真的。

Anybody can make mistakes.⼈都会犯错误。

（3）表许可（常⽤于⼝语中）。

Can/Could I go now?我可以⾛了吗？
He said I could use the computer.他说我可以⽤计算机。

Father said we could go to the concert.⽗亲说我们可以去参加⾳乐会。

-Could I borrow your dictionary? 你把字典借给我可以吗？
-Yes, of course you can. 当然可以。

（4）表惊异怀疑、不相信等态度
①主要⽤于否定句、疑问句和感叹句中，表惊异怀疑、不相信等态度。

Where can/could they be now?他们现在能在哪⼉呢？
What can he mean?他会是什么意思？
②如果跟完成时，则表⽰对过去发⽣的事的怀疑和不肯定。

could⽐can更加不肯定。

Can he have left already?他会是⾛了吗？
Could she have forgotten my address?她会把我的地址忘了？
It couldn't have been Xiao Wang. He has gone to the factory.那不可能是⼩王，他去了⼯⼚。

-There were already five people in the car but they managed to take me as well. 车上本来已经有五⼈，但他们还是设法把我也带上.
-It couldn't have been a comfortable journey.那次旅⾏不可能舒服。

注意：当说话的⼈对⼀件事表⽰肯定的判断时⽤情态动词must，当说话的⼈对⼀件事持否定的态度，这种判断⽤情态动词can’t或couldn’t。

The man with glasses must be Tom's father. They look alike. 戴眼镜的那个⼈肯定是汤姆的⽗亲。

他们看起来很像。

Jack can't be in the classroom. I saw him on the playground just a moment ago. 杰克不可能在教室⾥。

我刚才看见他在操场上。

③“could+完成时”，有时表⽰“过去本能够完成的事⽽没完成”。

You could have done the work better.你本来能做得更好些。

（事实并⾮如此）
You could have caught the early train.你本来能赶上早班⽕车。

（事实上没有）
--I stayed at a hotel while in New York. 我在纽约住在⼀家旅馆。

--Oh, did you? You could have stayed with Barbara. 是吗？你本可与巴巴拉住在⼀起的。

（5）表⽐较委婉客⽓地提出请求。

这时could和can没有时间上的差别，只不过⽤could⽐⽤can显得更加委婉客⽓。

Can you change a pound note for me , please?请你兑换⼀英镑零票给我好吗？
Could you tell me the right time please?请你把准确的时间告诉我好吗？
2、may和might
（1）表⽰许可或征询对⽅许可。

You may go now.现在你可⾛了。

May I watch TV after supper?晚饭后我可以看电视吗？
He said that I might use the telephone.他说我可以⽤电话。

注意：征询许可时，might⽐may更恭敬有礼。

may的否定形式为may not，但表⽰“不可以”、“阻⽌”等意思时常⽤must
not(musn't)代替may not。

Might I have a word with you , please?我可以和你谈⼀谈吗？
-May I take the book out of the reading-room? 我可以将这本书带出阅览室吗？
-Yes , you may./No, you musn't./No, you may not./No, you'd better not.
是的，可以/不，不⾏。

（2）表可能性，有“或许、可能”之意
might与may可以换⽤，但might表⽰较多的怀疑、更加不肯定、语⽓更委婉。

He may/might be English.他可能是英国⼈。

They may/might have a lot of work to do.他们可能有许多⼯作要做。

Peter may come with us tonight, but he isn't very sure yet. ⽪特今晚可能和我⼀起来，但他还没定。

注意：may表可能⼀般不⽤于疑问句，在疑问句中通常⽤can/might,或者以be likely to结构出现。

Can it be true?这可能是真的吗？
What can she be thinking of?她可能在想些什么？
Migh t I make a suggestion?我可以提个建议吗？
Is he likely to win the match?他有可能赢这场⽐赛吗？
（3）"may/might+完成时"，表⽰对过去事情的推测，might⽐may更含蓄，委婉，或更加不肯定。

Sorry,I’m late. I might have turned off the alarm clock and gone back to sleep again. 对不起，我可能是把闹钟关掉了⼜睡着了。

She may/might have gone to the library.她可能到图书馆去了。

She may/might have missed the plane.她也许没赶上飞机。

（4）"might+完成时"表⽰过去本可以⼲的事⽽没⼲。

You might have told me earlier!你本来可早点告诉我。

（⽽没告诉，表责备）
（5）⽤于表⽬的或让步状语从句中。

She was studying English so that she might read English books.她正在学习英语，以便能阅读英⽂书籍。

He died in order that others might live. 他为了别⼈⽽牺牲了。

（6）表祝愿（不能⽤might）。

May all our dreams come true.愿我们梦想成真。

May that day come soon.愿这⼀天早⽇到来。

3、must和have to
（1）must表⽰“必须”，“应该”。

否定式must not(mustn't)表⽰“不应该”，“不许可”，“不准”,“禁⽌”等。

在回答带有must的问句时，否定式常⽤need not(needn't)或don't have to 表⽰“不必”，⽽不⽤must not (mustn't)。

The work must be finished as soon as possible.这件⼯作必须尽快完成。

You mustn't speak like that.你不能那样说话。

—Must I be home before eight o'clock? 8点之前我必须回家吗？
—Yes, you mus t./No, you needn't./No, you don't have to. 是的，必须回家。

/不，不必了。

（2）must表推测，
①⼀般只⽤于肯定句中，译成汉语“⼀定”，“必定”。

There must be some mistakes.肯定有⼀些错误。

You must be very tired.你⼀定很累了。

②如果表⽰对过去事情的推测，就⽤"must+完成时"。

You must have left your umbrella in the theatre.你⼀定把⾬伞丢在剧院⾥了。

His car is still here. He must have gon e by bus.他的车还在这⾥，他⼀定乘公共汽车⾛了。

③当must表推测之意时，其否定形式常⽤can not⽽不⽤must not。

He can't have been to your home. He doesn't know your address.他不可能到过你家，因为他不知道你的住址。

What can he be doing at this time of night?夜晚都到这个时候了，他究竟在⼲什么呢?
（3）must表必然性
You mus t catch cold if you don't put on more clothes.如果你不多穿些⾐服，必然感冒。

All men must die.⼈固有⼀死。

Truth must be out.真相总会⼤⽩。

（4）have to表⽰“必须”，“不得不”，在这个意义上与must很接近，但must表⽰的是说话⼈的主观看法，⽽have to 表⽰的却是客观需要。

I have to go now.我得⾛了。

（客观需要）
I must go now.我必须⾛。

（主观看法）
You have to work hard to make a living.为了谋⽣你就得努⼒⼯作。

（客观需要）
You must do what I tell you.你必须按照我告诉你的去做。

（主观要求）
（5）have to 有更多的时态形式：现在时，过去时，将来时等，⽽must只有现在时形式。

We had to be there at 8.我们得8点到那⾥。

I shall have to go to school tomorrow.明天我得去上学了。

（6）have to 不能代替表推测的must，但在虚拟条件句中⽤had had to+动词原形表⽰与过去相反的情况。

You must be joking.你⼀定是在开玩笑。

（不能⽤have to）
If I had had to do the work, I should have done it in a different way.如果我不得不做这项⼯作，我会以不同的⽅式去做。

（不能⽤must）
If I had had to run the factory, I would have had it run by able men.如果我得管理那家⼯⼚的话，我就会让能⼈来管。

（不能⽤must）
4、ought to
（1）ought没有⼈称或时态的变化，后跟带to的不定式。

常译作“应该”，“应当”等，和should同义，只是⼝⽓稍重⼀些。

其否定式为ought not to (oughtn't to )，疑问式为Ought I /you to…?
You ought to start at once你应该⽴刻出发。

Such things ought not to be done.这种事不应该⼲。

-Ought he to go? 他应该⾛了？
-Yes, he ought to.是的，应该⾛了。

（2）表可能性
Mary ought to be home by now.玛丽这会⼉该是到家了。

There is a fine sunset. It ought to be a fine day tomorrow.今天有晚霞，明天应该是个好天。

It ought to be a fine day tomorrow morning.明天旱晨⼤概是个好天⽓。

（3）表⽰没有履⾏过去的义务时，⽤“ought to +完成时。

You ought to have tol d me about this earlier.(But you didn't)你本来应该早⼀点把此事告诉我。

（但没有）
I ought to have written that letter yesterday.(But I didn't)我本应该昨天写那封信。

（但我没写）It ought to have been don e long ago.这事早该做完的。

5、used to
used to只有⼀种存在形式,⼀般过去式。

具体⽤法如下：
（1）在肯定句中，表⽰现在⼰经不再发⽣，不复存在的过去的⾏为或存在的状态。

He used to smoke 20 cigarettes a day.他过去每天抽20⽀烟。

There used to be a building there.那⾥曾经有座⼤楼。

（2）used to 通常只能跟不定式，但偶尔也能跟进⾏时，意思⼀样。

He used to be always making jokes.他过去总爱开玩笑。

（3）在疑问句、否定句或强调句中，可以有两种形式：
Used you to go to work by bike?
Did you use to go to work by bike?你过去常骑车上班吗？
He usedn't to smoke as much as he does now.
He didn't use to smoke as much as he does now. 他过去不像现在抽这么多烟。

I certainly used to play football, but it was a long time ago.
I certainly did use to play football, but it was a long time ago.我过去的确常踢⾜球，但那是很久以前的事了。

（4）在反意疑问句或简略回答中，也有两种形式：
John used to be very fat, didn't he/usedn't he?约翰曾经很胖，是吗。

—Used you to live in Shanghai?—你过去曾住在上海？
—Yes, I did/ I used to.—是的。

（5）used to 与would的区别：
情态动词used to 和would都可以表⽰过去的习惯性动作，但有下列不同点：
①used to 表⽰确定的过去时间，不需与确定的过去时间连⽤，⽽would⼀般与时间状语连⽤。

used to 含有与现在相⽐较的意思，⽽would没有。

He used to get up early.他过去常常早起。

(现在不早起了)
The old man would go to the park every day to have morning exercises.那位⽼⼈以前每天都去公园晨练。

（没有与现在相⽐较的意思）
②used to 指过去反复发⽣或持续发⽣的动作，⽽would仅指过去反复发⽣的动作，不指持续发⽣的动作；另外，used to 既表动作还表状态，⽽would只表动作不表状态，因此下列句中的used to 不能⽤would 代替。

People used to think that the earth was flat.⼈们过去认为地球是平的。

She used to be very nervous in the exam.她以前考试常常很紧张。

③used to 表客观事实，would则表⽰⼀种意愿。

When he lived by the sea, he used to suffer diseases.他住在海边时，经常有病。

（used to 不能
换成would）
There used to be a small village here.这⾥曾经有⼀个⼩村庄。

6、dare
dare作情态动词表⽰“敢”，主要⽤于否定句、疑问句和感叹句，⽆词形变化，单数第三⼈称不加-s。

（1）通常⽤于否定句和疑问句，其⽤法同其他情态动词。

She daren't even look out.她甚⾄不敢向外看。

Dare you go to school by yourself?你敢独⾃⼀⼈去上学吗？
How dare you say I am unfair?你怎么敢说我不公平!
I dare not sleep in that room again.我再也不敢睡在那房间了。

（2）dare在下列情况下，也⽤于肯定句中。

①句⼦含有否定意义或疑问意义时。

I hardly dare think of it.我简直不敢想这事。

He asked me whether I dare swim across the river.他问我是否敢游过河。

I wonder how he dared say that to the teacher.我不知道他怎么敢那样和⽼师说话。

②在简略答语中。

—You daren't climb that tree, dare you?你不敢爬那棵树，对吗？
—Yes , I dare.不，我敢。

③状语从句中。

I won't allow you to swim across the river, even if you dare do it.即使你敢，我也不愿你游过河去。

（3）dare既表现在和将来，也表过去。

Alice was afraid and dare not go. 艾丽丝害怕，不敢去。

注意：从上下⽂看不出具体时间时，通常不⽤情态动词dare，⽽⽤实义动词的过去时。

She dared to go.她敢去。

She didn't dare(to)go.她不敢去。

7、need
（1）表⽰"必要;必须"，通常⽤于否定句和疑问句
Need he work so hard? 他需要这么⽤功吗？
You needn't worry about it. 你不必为此担忧。

I hardly need say how much we missed you. 不必说我们多么的想念你。

（2）在肯定句中，它被must或have to 取代。

—Need I come? —我需要来吗？
—Yes, you must/have to.—需要。

You needn't see him, but I must /have to.你不必去看他，但我必须去。

（3）“need+⼀般式”，通常表现在和未来，有时也可指过去。

She need not come. 她不必来。

（现在或将来）
We were told that we needn't do that.我们被告知不必做那事。

（过去）
Need she go yesterday?她需要昨天⾛吗？（过去）
如果从上下⽂看不出具体时间时，通常不⽤情态动词need表过去，⽽⽤实义动词need的过去时或had to 表⽰。

She didn't need to come.
She didn't have to come
She had not to come.她不必来。

（4）“need+完成时”表⽰过去不必做⽽实际做了的事。

You needn't have hurried.你本不必这么匆忙。

Peter needn't have done it yesterday.彼得昨天本不必做这件事。

8、shall
（1）⽤在疑问句中，⽤来征求对⽅意见或请求指⽰或向对⽅提出建议，⽤于第⼀、三⼈称。

—Shall I tell John about it? 咱们把这件事告诉John好吗？
—No, you needn't. I've told him already. 你不必了。

我已经把这件事告诉他了。

Where shall I wait for you?我在哪⾥等你。

Shall we start the meeting now?我们现在开会好吗？
Shall those books be sent over to you at once?那些书⽴即给你送过来吗？
（2）⽤于第⼆、三⼈称，可表⽰说话者的⼀种决定、允许或威胁。

If you work hard, you shall have a holiday on Sunday.如果你努⼒⼯作，星期天就可以休假。

（允许）
She shall do it, whether she wants or not.不管她愿意不愿意，她必须做这件事。

（决定）
He shall suffer for this.He shall pay you what he owes you.他必将⾃⾷其果，他⽋的债⼀定得还。

（威胁）
9、should
（1）表“劝告、建议”时，可译成“应该”，这时可⽤ought to替换。

You should keep your promise.你应该遵守诺⾔。

Young people should learn how to use computers. 年轻⼈应该学如何应⽤计算机。

（2）表⽰委婉陈述⾃⼰的意见。

I should think you are right.我想你是对的。

I should advise you not to go now.我劝你现在别⾛。

（3）表⽰惊异赞叹、忧虑、惋惜、欢欣、不满等情绪。

Why should you think so?你为何这样想呢？（不满）
It's strange that it should be so hot today.很奇怪，今天怎么这么热。

（惊奇）
It's wonderful that you should have achieved so much in these years.这⼏年你们有了这样⼤的成绩，真了不起。

（赞叹）（4）表推测
意为“可能，该”，表⽰对现在情况、将来情况的推测。

They should be home by now.他们现在应当到家了。

The book you need should be in our library.你需要的那本书我们图书馆应该有。

It’s nearly seven o’clock. Jack should be here at any moment.现在快要七点了，杰克随时会到。

-When can I come for the photos? I need them tomorrow afternoon. 我什么时候能取照⽚？明天下午要⽤。

- They should be ready by 12:00.明天12点前应该能冲好。

（5）“should+完成时”，在肯定句中，表⽰应完成⽽实际未完成的事情；如果⽤在否定句中，则表⽰发⽣了不应当发⽣的事件。

I told Sally how to get here, but perhaps I should have written it out for her.我和萨丽说了
怎样来这⾥，或许我应该给她写清楚。

You should have stopped at the red light.你见了红灯本应该停车。

（未停）
You should not have gone back to work without the doctor's permission.你未经医⽣许可不应该回去⼯作的。

（回去了）10、will
（1）表意志、意愿、允诺，可⽤于多种⼈称。

I will tell you all about it.我愿告诉你⼀切。

（意愿）
We'll help him if he asks us to.如果他让我们帮忙，我们⼀定会帮的。

（表意志）
Come whenever you will.你随时都可以来。

（允诺）
If he will come into the hall, the meeting will begin soon.请到⼤厅来，会议快要开始了。

If you will make another try, I shall do everything possible to help you.如果你愿意再试⼀次的话，我愿意尽⼀切可能帮助你。

Say who will, nobody believes it.不管他说什么也没⼈相信。

（2）⽤于第⼆、第三⼈称的疑问句中，表询问或请求。

I'm going to the library.Will you go with me? 要去图书馆，你愿与我⼀起去吗？（询问）
Will you give him a message when you see him? 见到他时，请给他个信好吗？（请求）
（3）⽤于第⼆、三⼈称表推测。

That man with the book will be Mr. mith.拿书的那个⼈可能是史密斯先⽣。

You will remember the story I told you the other day.你⼤概还记得我那天给你们讲的故事。

（4）有时表⽰⼀种习惯性动作，常⽤于第三⼈称。

Fish will die out of water.鱼离开⽔就不能活。

She will sit there for hours doing nothing.她往往会坐在那⼉⼏⼩时，什么也不⼲。

11、would
（1）would是will的过去式，表⽰过去时间的意志、意愿、决⼼，⽤于各种⼈称。

They said they would help us.他们说他们愿意帮助我们。

I promised that I would do my best. 我承诺我决⼼尽最⼤努⼒。

（2）would表⽰说话⼈的意愿或向对⽅提出请求，语⽓⽐will婉转，仍指现在时间。

Would you like some bananas?你喜欢吃⾹蕉吗？
I'd like to see your new bike.我希望看看你的新⾃⾏车。

Wouldn't it be better to leave tomorrow?明天离开是不是更好？
（3）表⽰过去习惯发⽣的动作(与used to有区别，见used to)。

When he was there, he would go to that coffee shop at the corner after work every day. 他在那⾥时，他每天下班后都到拐⾓处那家咖啡店去。

The old worker would often go to the park to play chess.那位⽼⼯⼈过去常去公园下棋。

She would come to see me now and then.她时常来看我。

（4）表⽰推测。

That would be his father.那⼤概是他⽗亲。

You would be about 10 years old then.你那时⼤概10岁左右。

12、had better(best)+动词原形，would rather+ 动词原形+than +动词原形,would rather+虚拟式丛句
①had better(best)+动词原形意为“最好”，否定形式had better not,疑问句把had放在主句前。

这个结构⽤于现在时或⼀般将来时，通常⽤于所有⼈称。

We'd better not invite him.我们最好不要邀请他。

You'd bette r stay at hospital for another few days.你最好在医院再住⼏天。

Better have the operation right now.你最好还是现在就动⼿术。

Had he better set off at once? 他马上动⾝好吗？
②would rather意为“宁愿，宁可”，后接动词原形，否定式为would rather not, 疑问句把would放在主语前。

Would rather…than 意为“宁愿……⽽不”，than后⾯接动词原形（不带to），would rather 后⾯接从句时要⽤虚拟式。

Which would you rather do, go to cinema or stay at home? 你是去看电影还是待在家⾥？
He would rather die t han surrender. 他宁死不投降。

I w ould rather you hadn’t lent her the bike the other day.我宁愿你前些⽇⼦不借给他⾃⾏车。

I would rather he stayed at home.我宁愿他呆在家中。

五、“情态动词+be doing”的⽤法
1、推测或评论某动作是否正在进⾏
Our teacher must be correcting our exam papers.我们的⽼师想必在批改试卷。

He can't be working now.他不可能正在⼯作。

We may be playing tennis at nine tomorrow.明天九点我们可能在打⽹球。

2、表⽰“即将；将要”这类意思
I must be going now.我现在必须⾛了。

She may be leaving tomorrow.她可能明天离开。

3、⽤来表⽰“⽼是做某事”
If you really want yourself to be in good health, you must not always be smoking so much.如果你想要⼀个好的⾝体，就不该⽼是抽这么多烟。

Why should you always be finding fault with that girl?怎么⽼是找那个姑娘的岔⼦?
Sir, you oughtn’t to be sitting in the waiting room. It is for women and children only.先⽣，你不该总是坐在这个等候室，这⾥是妇⼥⼉童专⽤。

六、“情态动词⼗have done”的⽤法
1、can have done的⽤法
can have done⽤于对过去动作的推测，表⽰“可能”，常⽤于否定句和疑问句。

She can't have gone to work. It's Sunday.她不可能去上班，今天是星期⽇。

She is two hours late. What can have happened?她已经晚了两个⼩时，可能会发⽣什么事情呢? -Do you think our
basketballers played very well yesterday? 你认为我们的篮球队员打得好吗？- They couldn’t have done better. 他们从来没有打这么好过。

2、must have done的⽤法
must have done⽤于对过去动作的推测，表⽰"可能⼀定……"，⽤于肯定的陈述句中。

I have not seen him for quite a long time. He must have been very busy.我很久没见他了，他⼀定很忙。

I didn't hear the phone, I must have been asleep. 我没听到电话，我肯定是睡着了。

3、may have done的⽤法
may have done⽤于对过去动作的推测，表⽰ "或许;可能"，多⽤于肯定句和否定句。

She is late. She may have missed the bus.她迟到了，她可能没赶上车。

He may not have read the book.他也许没有看过那本书。

He might have given you more help, even though he was very busy.即使他很忙，他可能会给你很多帮助。

4、ought to/should have done的⽤法
ought to/should have done的肯定形式表⽰"过去应该做的事⽽没有做"，其否定形式表⽰ "过去不该做的事却做了"，含有批评的意思。

Jenny should have kept her word. I wonder why she changed her mind. 詹妮应该信守诺⾔。

我不知道她为什么改变了主意。

You ought to have paid more attention to your lessons.你本应该多注意⾃⼰的功课的。

She ought not to have kept us waiting so long.她不应该让我们等那么长时间。

I shouldn't have ordered the equipment without asking you first.我不该预先不请⽰你就订购了设备。

I was really anxious about you. You shouldn’t have left home without a word.我们是在为你着急，你不该⼀声不吭就离家。

We should have studied last night, but we went to the concert instead. 我们昨晚该学习来，⽽我们去了⾳乐会。

Tom ought not to have told me your secret, but he meant no harm.汤姆不应该告诉我你的秘密，但他没恶意。

5、need have done的⽤法
need have done⼀般多⽤于否定句或疑问句中，表⽰“本来不必做的事却做了”。

You needn't have told that to him.你本来没有必要把那事告诉他。

(实际却告诉了) You needn’t have hurried.你本来不必这么匆忙。

(却忙了⼀阵⼦)
There was plenty of time. She needn’t have hurried. 还有时间，她没必要如此匆忙。

6、could have done的⽤法
could have done表⽰对过去动作的推测，作⽤和can have done相同，但表达的可能性较⼩或说话⼈更加不肯定。

John could have overslept again.约翰可能⼜睡过头了。

could have done有时表⽰“过去本来能做的事⽽实际上却没有做”。

You could have come here a little earlier.你本来可以早⼀点到这⾥来的。

7、might have done的⽤法
might have done表⽰程度上⽐may更⼩的可能性。

He might have arrived home by now. Let's ring him up again.现在他可能已经到家了，我们再给他打⼀次电话吧。

might have done有时表⽰“本来可以做的事⽽实际上没有做”，含有“劝告，责备”的语⽓。