高考英语情态动词用法详解，想要满分的看过来,我们一起来学习吧，下面小编就和大家分享，来欣赏一下吧。
高考英语情态动词用法详解，想要满分的看过来
情态动词的区分 情态动词可以广泛分为四大类。第一类只能做情态动词，包括may、might、must等。第二类既能做情态动词，又能做实义助词，包括need、dare、can等。第三类既能做情态动词，又能做助动词，包括shall、should、will、would等。第四类是指具有情态动词特征的短语，包括have to、used to、ought to等。Can/could通常代表许可的意思，能够广泛用于肯定句、否定句和疑问句中，而且could的表达效果通常要更加委婉。Cannot是指“禁止”，通常用于警告和告示。May/might的意思与can/could相似，用法也没有明显区别，不过其与后者相比大多用于正式文体，通常含有尊敬之意，其中，might较may表达的效果更加委婉，但不是很常用。Shall通常用于表示征求意见，常用于疑问句中。而will/would同样是表示请求，其中would的表达效果更为客气委婉，且大多用于第二人称。Must则是表示必须、必要。
情态动词的用法
重点学习：will ( would), can (could), may (might)。will 1.客观情形
主语自己不能做决定，不要受客观情形支配。如I will be 18 years old next month. 下个月我就要18岁了。这里的will和将来时态连用表明是受时间客观规律支配的，不以主观意志来做主的。因此可以和一个词组be going to do 区别开来。be going to do 也是将要的意思，用法和will有很大区别。当be going to do 的主语是人的时候，意思为“打算，计划”;只有当其主语是物的时候才可以和will等同表示马上要发生，但是依然不可以用于表示自然规律的情形。It is going to rain soon.= It will rain soon. 马上就要下雨了。If heated up, ice will turn into water. 如果加热，冰就会变成水。这是自然现象和规律。不可以使用be going to。自己不能做主，需要争求意见的时候——问询别人是否需要本人提供的帮助时。如Will I cook noodles for you? 我给你煮点面吃好吗?
2.主观态度 (1)表意愿。 Will you marry me? 你愿意嫁给我吗?Yes,I will. 我愿意。will 的名词意思是意志，意愿，和遗嘱。At will 随心所欲，想怎么样就怎么样。willing就是派生出来的形容词，be willing to do= be ready to do乐意去做。(2)主观判断，表示非常肯定的判断和认同 Boys will be boys. 男孩子毕竟是男孩子。Master will be master. 大师就是大师。(3)表示对能力的估计 Having enough money, I will travel around the world. 如果有钱了，我就可以周游世界了。(4)希望和请求 Will you turn down the TV volume a little bit? 你把电视音量调小点好吗?一般来说，用will原形的时候多用于熟人朋友间，和第一次见面的人说话，要注意礼貌，因此would you turn down the TV volume a little 更合适。can 1.客观情形 A.主语自己不能做决定，不要受客观情形支配。By the end of next month, we can have learned 2000 words. 到下个月底的时候，我们就会学完2000个词汇了。这里的can和will都可以表示受时间的支配。Water can turn into ice when frozen. 水如果冰冻就会结冰。自然规律和will 一样可以替换。B. 自己不能做主，需要争求意见的时候——问询别人是否允许自己是否可以做什么的时候。Can I use your phone?我可以用一下你的手机吗?Yes, you can. 当然可以。No, you can’t. 你不能(你不被允许)。此时也可以用may来替换。May I use your phone? 我可以用一下你的手机吗?Yes, you can. 当然可以(注意 回答的时候用can居多)，No, you can’t. 此时不可以回答may not.2. 主观态度 (1)意愿。 I can help you if you give me 100 dollars. 如果你给我100元，我就愿意帮助你了。但是这是属于非正式的用法，如果正式场合问询别人意愿的时候还是应该选择will.(2)主观判断，猜测。 A. 把握并非很足的判断 相当于may。This upcoming exam can be difficult, for the teacher gives us an extra review class on it.马上到来的考试可能会很难，因为老师为了考试给我们加了额外的复习课。此处可以用may取代。B. 用于may 和must 表示猜测时候的否定。(3)表示对能力的估计。 这种能力往往都是先天获得的，或者已经具备很久的。而be able to 表示能力的时候，一般是可以用于具体时态中，而can只有一般时和过去时，而且不和具体时间状语连用。I can sing quite a few English songs. 我可以唱好多英语过去。表示的含义是我学过很多英语歌曲，任何时候都可以唱出来。The candidates are able to have the chance to meet the HR manager after winning the first interview.在初次面试成功后，求职者能够有机会和人力资源的经理见面。此时Be able to 用于具体时刻前。
could 希望和请求 和will 一样，和熟人用can, 和陌生人用could更礼貌。Can you give me a hand? 你可以帮助我一下吗?Could you please give me a hand? 您可以帮助我一下吗?(更客气)may 1.客观情形 主语自己不能做决定，不要受客观情形支配。May I come in? 我可以进来吗?No, you can’t. 否定形式只可以是can’t, 不可以是may not.这是因为：根据词源学(etymology)may 来自于might(权力，权威，威严)。may not 的意思有两个：1. 权威迫使下，不能做……2. 表示猜测，表示不可能。2.主观态度。 A. 把握并非很足的判断。It may not be his fault. 这也许不是他的错。B. 严格禁止。may not do= mustn’t do = shouldn’t doStudents mustn’t / may not bring cellphone into campus. 校园内严禁携带手机。
语法 | 情态动词的用法整理，非常实用!
情态动词
定义:
情态动词是一种本身有一定的词义,但要与动词原形一起使用，给谓语动词增添情态色彩，表示说话人对有关行为或事物的态度和看法，认为其可能、应该或必要等。
情态动词后面加动词原形。
分类：
情态动词有四类：
①只做情态动词：must,can(could),may(might),ought to
②可做情态动词又可做实义动词：need,dare
③可做情态动词又可做助动词：shall(should),will(would)
④具有情态动词特征：have(had) to,used to
位置:
情态动词在句中放在谓语动词之前, 谓语动词前若有助动词,则在助动词之前,疑问句中, 情态动词则在主语之前。
I can see you. Come here.
我能看见你，过来吧。
He must have been away.
他一定走了。
What can I do for you?
我能帮你吗?
How dare you treat us like that!
你怎能那样对待我们!
特点:
情态动词无人称和数的变化, 情态动词后面跟的动词需用原形,否定式构成是在情态动词后面加 "not"。 个别情态动词有现在式和过去式两种形式, 过去式用来表达更加客气, 委婉的语气, 时态性不强, 可用于过去，现在或将来。情态动词属非及物动词，故没有被动语态。情态动词没有非谓语形式，即没有不定式，分词，等形式。
He could be here soon.
他很快就来。
We can't carry the heavy box.
我们搬不动那箱子。
I'm sorry I can't help you.
对不起，我帮不上你。
基本助动词与情态助动词最主要的区别之一是，基本助动词本身没有词义，而情态助动词则有自己的词义，能表示说话人对有关动作或状态的看法，或表示主观设想：
What have you been doing since? (构成完成进行体，本身无词义)
I am afraid I must be going. (一定要)
You may have read some account of the matter. (或许已经)
除此之外，情态助动词还有如下词法和句法特征：
1) 除ought和used以外，其他情态动词后面只能接不带to的不定式。如果我们把ought to和used to看做是固定词组的话，那么，所有情态动词无一例外地只能接不带to的不定式：
We used to grow beautiful roses.
I asked if he would come and repair my television set.
2) 情态助动词在限定动词词组总是位居第一：
They need not have been punished so severely.
3) 情态助动词用于第三人称单数现在时的时候，没有词形变化，即其词尾无-s形式：
She dare not say what she thinks.
4) 情态动词没有非限定形式，即没有不定式和分词形式，也没有相应的动名词：
Still, she needn't have run away.
5) 情态助动词的“时”的形式并不是时间区别的主要标志。在不少场合，情态助动词的现在时和过去时形式都可以表示现在、过去或将来时间：
Would you mind very much if I ask you to do something?
She told him he ought not to have done it.
6) 情态助动词之间是相互排斥的，即在一个限定动词词组中只能出现一个情态助动词，但有时却可以与have和be基本助动词连用：
You should have washed the wound.
Well, you shouldn't be reading a novel.
用法
首先它是动词，而且不同于行为动词，行为动词表示的是可以通过行为来表达的动作(如写，读，跑)，而情态动词只是表达的一种想法(如能，也许，敢)。
用法是：情态动词+行为动词原形
例句：I can read this sentence in English.
我能用英语读这句话。
情态动词是一种本身有一定的词义,表示说话人的情绪,态度或语气的动词,但不能单独作谓语, 只能和其他动词原形构成谓语。
We can be there on time tomorrow.我们明天能按时去那儿。
May I have your name? 我能知道你的名字吗?
Shall we begin now?我们现在就开始吗?
You must obey the school rules.你必须遵守校规。
情态动词数量不多,但用途广泛,主要有下列:
can (could), may (might), must, need, ought to, dare (dared), shall (should), will (would),have (to) ,had better.
功能
助动词(auxiliary)主要有两类：基本助动词(primary auxiliary)和情态助动词(modal auxiliary)。基本助动词有三个：do, have和be;情态助动词有十三个：may, might; can, could; will, would; shall, should; must, need, dare, used to, ought to. 上述两类助动词的共同特征是，在协助主动词构成限定动词词组时，具有作用词的功能：
1) 构成否定式：
He didn't go and neither did she.
The meeting might not start until 5 o'clock.
2) 构成疑问式或附加疑问式：
Must you leave right now?
You have been learning French for 5 years, haven't you?
3) 构成修辞倒装：
Nowhere can he obtain any information about his sister.
Hardly had he arrived when she started complaining.
4) 代替限定动词词组：
A: Who can solve this crossword puzzle?
B: Tom can.
A: Shall I write to him?
B: Yes, do.
情态动词的用法要点
一. can和could
情态动词 用法 例句
can/could
表示能力(体力、知识、技能)
(表示过去有能力用could)
1.“I don’t think Mike can type.”
2.I can speak fluent English now , but I couldn’t last year.
3.Can you lift this heavy box?(体力)
4.Mary can speak three languages.(知识)
5.Can you skate?(技能)
6.Two eyes can see more than one. 两只眼比一只眼看得清。
7.Could the girl read before she went to school? 这女孩上学前能识字吗?
在肯定句中，表示客观可能性，(客观原因形成的能力)。并不涉及具体某事会发生，常用来说明人或事物的特征。要表达具体某事实际发生的可能性时，不用can，需用could，may，might。1. As a human being, anyone can make a mistake.
2. I’m confident that a solution can be found.
3. He can be very forgetful sometimes.
4. I may stay at home this weekend.(实际可能性)
5. Peter might come to join us.(实际可能性)
6. It will be sunny in the daytime ,but it could rain tonight.(实际可能性)
7. 7.They’ve changed the timetable, so we can go by bus instead.
8. 8.This hall can hold 500 people at least.
9. The temperature can fall to –60℃, that is 60℃ below freezing.
气温可降至—60℃，也就是零下60℃。
10. 11..He can´t (couldn´t) have enough money for a new car. 他不可能有足够的钱买新车。
11. 12 You mustn´t smoke while you´re walking around in the wood. You could start a fire. (实际可能性)
12. 在林子里走时勿吸烟，那样可能会引起火灾。
表示请求和允许。表示请求，口语中常用could代替can，使语气更委婉。
用can和 may来回答，不能用could或might。1.Can we turn the air conditioner on?
2.Any police officer can insist on seeing a driver’s license.
3.In soccer, you can’t touch the ball with your hands.
4.Could you have her call me back when she gets home, please?
5.I wonder if I could just ask you to sign this.
6. Could I borrow your dictionary?
---Yes, of course, you can.
No, I'm afraid not/No,you cann’t/No,you may not.
表示对现在的动作或状态进行主观的猜测，主要用在否定句和疑问句中。1. It can’t be easy caring for a man and a child who are not your own.
2. Can the man over there be our head master?
3.If Tom didn't leave here until five o'clock, he can't be home yet. 如果汤姆五点才离开这儿，他此时一定还未到家。
表示惊异、怀疑、不相信等态度，主要用在否定句、疑问句和感叹句中。1. Can this be an excuse for not giving them help?
2. This can’t be true.
3. How can you be so crazy.
4. 4.Can this be true?
5. 5.How can you be so careless!
6. 6.This cannot be done by him.
7. Where can (could) they have gone to? 他们会去哪儿了呢?
8. He can´t (couldn´t) be over sixty. 他不可能超过六十岁。
9. How can you be so careless? 你怎么这么粗心?
10. 特别说明：
(1) could用来表示请求时，语气委婉，主要用于疑问句，不能用于肯定句，答语应用can(即：could不能用于现在时态的简略答语中)。如：
——Could I use your dictionary?
——Yes, you can.(否定回答可用：No, I’m afraid not.)
此时可与may互换。在疑问句中还可用could,
might代替，不是过去式，只是语气更委婉，不能用于肯定句和答语中。
---- Could I come to see you tomorrow?
---- Yes, you can. ( No, I’m afraid not. )
(2) can和be able to辨析
can(could)和be able to都可以表示能力，意思上没有区别。但can只有现在式和过去式，而be able to则有更多的形式。如：
I’ve always wanted to able to speak fluent English.
Those bags look really heavy, are you sure you’ll be able to carry them on your own?
但是，表示在过去某时的某一场合经过一番努力，终于做成了某事，通常不用could，而用was/were able to来表示。could：有潜能，但并未做到
这时，was/were able to相当于managed to do或succeed in doing。如：
After the accident it was a long time before she was able to walk again.
The fire was very big, but most people were able to escape from the building.
I can sing many English songs.我会唱许多英文歌曲。
We were able to return to our campsite before the heavy rain.我们在下大雨前设法会到了野营地。
He was able to swim across the river and escaped being caught.他游到了河对岸，没有被抓住。
在否定句中，can/could与be able to几乎没有什么差别，两者可以互换。例如：
She wasn’t able to/couldn’t cook French dishes.她不会做法国菜。
(3) 惯用形式“cannot …too…”表示“无论怎么……也不(过分)”。如：
You cannot be too careful.你越小心越好。
惯用形式“cannot but+ 不定式(不带to)”表示“不得不，只好”。如：
I cannot but admire her determination.我不得不钦佩你的决心。
二．may和might
情态动词 用法 例句
may/might表示允许、请求。否定回答一般用must not/mustn’t,表示“禁止、阻止”之意，但也可以用had better not (最好别)或may not(不可以)，语气较为委婉。 1. May I come in and wait?
2. ——May I smoke here?
——No, you mustn’t(或No, you’d better not.)
在表示请求、允许时，might比may语气更委婉些。而不是过去式，用May I征询对方许可在文体上比较正式，在口气上比较客气，在日常用语中，用Can I征询对方意见更为常见。
否定回答时可用can’t
或mustn’t，表示“不可以，禁止”。
或者
肯定回答可以用 yes,please. / Certainly.1.Might I borrow your pen?
2.I wonder if I might speak to your son.
3. Might/ May I smoke in this room?
4. ---- No, you mustn’t.
5. 4. May/Might I take this book out of the room?
---- Yes, you can. (No, you can’t / mustn’t. ) \
You may drive the car.
— Might I use your pen? — No, you mustn't.
表示可能性的推测，通常用在肯定句和否定句中，含有“或许”“大概”“可能”之意;用might代替may时，则语气显得更加不肯定。1. It may rain this afternoon.
2. She might come to join us this afternoon.
3. I suppose he might have missed the train.
4.He may /might be very busy now.
5.Your mother may /might not know the truth.
may用于祈使句表示祝愿1. May you succeed.。
2. May you have many more days as happy as this one.
3. May she rest in peace.愿她安息。
惯用句式：
“may well+ 动词原形”，意为“完全能，很可能”，相当于to be very likely to
“may as well或might(just)as well+动词原形”意为“最好，满可以，倒不如,不妨",”，相当于“had better或there is no reason to do anything else.1. It may well change forever the way you look at Greek art.
2. There may well be a real problem here.
3. There is nothing to do, so I may as well go to bed.
4. You may as well tell us now, we’ll find out sooner or later.
5. I suppose we might as well go home.
6. And if you have to plough the field anyway, you might as well plant it at the same time.
7.If that is the case, we may as well try.
might 间接引语中指过去。表可以。1. He told me that I might smoke in the room. 他告诉我可以在房间里抽烟。
二． must和have to
情态动词 用法 例句
must表示“必须，应该，一定”之意，语气比should，ought to强烈。其否定形式mustn’t表示“不准，不应该，禁止”等意.1. You must come to school on time.
2. Everybody must obey the law.
3. You mustn’t drive so fast in the street.
4. We mustn’t waste any more time.
5. I must finish my work today.
6. Must I return the book tomorrow?
7. 7.The play is not interesting. I really must go now.
在回答带有must的问句时，否定回答常用needn’t或don’t have to，表示“不必”，而不用mustn’t.1.—Must I come back before ten?
—Yes，you must.(No, you needn’t)
2.Must we hand in our exercise books today?
— Yes, you must. (No, you don’t have to.)
表示有把握的推测，意为“一定、准是、想必”，只用于肯定句中。
它的否定或疑问式用can代替must1. This must be your pen.
2. You must be hungry after a walk.
3. There must be a hole in the wall.
4. You’re Tom’s good friend, so you must know what he likes best.
5. 5.Your mother must be waiting for you now.
6. He must be staying there.
7. 他现在肯定呆在那里。
试比较和第一种用法的区别
He must stay there.
他必须呆在那。
have to
也可拼做have got to。
8. “必须，不得不”，意义与must相近。但must表示的是说话人的主观看法，而have to则往往强调客观需要,有被动接受的意思。无疑问句形式，疑问句用must 代替。
9. 10. The film is not interesting. I really must go now.
11. I have to go now, because my mother is in hospital.
12. My brother was very ill, so I had to call the doctor in the middle of the night. 我弟弟病得很厉害，我只得半夜里把医生请来。(客观上需要做这件事)
13. 4. Must I clean all the room?
14. 5. I must go over the test paper again to see if there are any mistakes.我必须再检查一遍试卷看看是否有错误。
15. 6. The teacher said that there were many mistakes in my test paper, so I had to go over it again.老师说我试卷中有很多错误，所以我只好再检查一遍。
16. must只有一种形式，即现在式与过去式都是一种形式，在间接引语中must可用于表示过去时间.而have to则涉及各种人称、时态等方面的变化形式。
17. 18. 7..I had to work hard when I was your age.
19. 8..I will have to learn how to use a computer.
20. 9.In order to take the exam, we’ll have to finish the whole book by the end of this month .
21. 10. told her that she must give up smoking. 我叫她必须戒烟。
22.
两者的否定意义不同，mustn’t表示“禁止，不许”，don’t have to表示不必。1. You mustn’t go there.
2. You don’t have to go there.
四．shall和should
情态动词 用法 例句
shall用于第一，三人称构成的疑问句，表示征求对方意见或请求指示1. Shall I open the window?
2. Shall we say 6 o’clock, then?
3. What shall I get for dinner?
4.Shall we begin our lesson?
4. 5.When shall he be able to leave the hospital?
5. Shall the boy wait outside? 让那男孩在外面等吗?
用于第二、三人称陈述句中，表示说话人给对方的命令、警告、决心、允诺或威胁。1. Don’t worry, you shall get the answer this afternoon.(允诺)
2. He shall be sorry for it one day, I tell you. (警告)
3. You shall do as I say. (命令)
4. If you children don’t do as I tell you, you shall not go to the party. (威胁)
5. You shall fail if you don’t work hard.(警告)
6. He shall have the book when I finish it.(允诺)
7. He shall be punished.(威胁)
8.You shall do as I say. 按我说的做。(命令)
9.You shall have my answer tomorrow. 你明天可以得到我的答复。(允诺)
10.He shall be sorry for it one day, I tell you. 有一天他会后悔的，我告诉你。(警告)
11.Nothing shall stop us from carrying out the plan. 什么也不能阻止我们执行这项计划。(决心)
should表示劝告或建议，意为“应该”其同义词是ought to;在疑问句中，通常用should代替ought to1.What should I do?
2.Should I trust him?
3.You should read his new book.
4. You should go to class right away.
5.Should I open the window?
You should be polite to your teachers. 你对老师应该有礼貌。
You shouldn´t waste any time. 你不应该浪费时间。
表示推测，用在肯定句中，对现在的情况或可能发生的事的主观推测或期待。意为“想必，大概，或许”1. It should be a nice day tomorrow.
2. Try phoning Robert, he should be home now.
3. He should be around sixty years old.
4.The film should be very good as it is starring first—class actors.
这部新电影是一流演员主演的，估计拍得很好。
5.They should be home by now. 照说他们现在应当已经到家了。
还可以用在if引导的条件句中，表示一件事听起来可能性很小，但也不是完全不可能，相当于“万一”的意思。从句谓语用should+动词原形构成，主句都一定用虚拟语气1. Ask Tom to ring me up if you should see him. (你万一见到汤姆，请让他给我打个电话)
2. Should I be free tomorrow, I’ll come. (万一我明天有时间，我就过来)
3. If things should change suddenly, please let me know. (万一情况突变，请通知我)
4. Ask her to ring me up if you should see her. 你万一见到她，请让她给我打个电话。
5. If you should change
your mind, please let us know. 万一你改变主意，请通知我们。
6.Should I (If I should) be free tomorrow I will come. 万一我明天有时间，我就来。
用于疑问句或感叹句中，表示意外、惊异的情绪，意为“竟会”，与why，what，how，who连用，如果是疑问句。则不需要回答。1. Why should anyone want to marry Tony?
2. Don’t ask me. How should I know?
3.Why should you be so late today? 你几天怎么来得这么晚?
4. — Where is Betty living? — 贝蒂住在哪里?
— How should I know? — 我怎么会知道呢?
5.I don't know why you should think that I did it. 我真不知道你凭什么认为这件事是我干的。
表示说话人的一种谦逊、客气、委婉的语气。
① I should think it would be better to try it again. 我倒是认为最好再试一试。
② You are mistaken, I should say. 依我看，你是搞错了。
③ I should advise you not to do that. 我倒是劝你别这样做。
五．will和would
情态动词 用法 例句
will/would用于表示意志，愿望或意愿。will指现在，would指过去。1. He is the man who will go his own way. (他是个自行其是的人。)
2. They said they would meet us at 10:30 at the station.
3. I will never do that again.
4. They asked him if he would go abroad.
5.He said he would help me.
6.I’ll do my best to catch up with them.
7.I will do anything for you. 我愿为你做任何事。
8.None is so blind as those who won´t see. 不愿看的人眼最瞎。
9.If you will read the book, I´ll lend it to you. 如果你愿意读这本书，我会把它借给你。
They would not let him in because he was poorly dressed. 他们不让他进去因为他衣着破旧。
I said I would do anything for you. 我说过我愿意为你做任何事。
表示请求、建议等，will接近命令的口气。用would比用will委婉、客气。Would like to do = want to 想要，为固定搭配
否定句用will，一般不用would, won't you是一种委婉语气。1. Will you please take a message for him?
2. Would you please tell me your telephone number?
3.Will / Would you pass me the ball, please?
4 Would you like to go with me?
5. Would you like some cake?
6 Won't you sit down?
表示习惯或倾向，意为“总是，惯于”。Will指现在，would指过去。would表示过去习惯时比used to正式，且没有“现已无此习惯”的含义。
used to可表示过去的习惯动作和经常的情况，而would只表示过去的习惯动作,不表示状态和情况。
1. Fish will die without water.
2. People will talk. (人们总会说闲话。)
3. When we worked in the same office, we would often have coffee together.
4. During the vacation, he would visit me every other day.
5. The boy will sit there hour after hour looking at the traffic go by.
那男孩常常坐在那里好几个钟点，看着车辆行人通过。
6.He used to ∕would smoke while writing. 过去他写东西时常抽烟。
7.She used to be fat. 她过去很胖
表示推测，意为“很可能，大概”。will表示推测比should把握大，比must把握小。1. These things will happen.
2. That will be the messenger ringing.
3. It would be about ten o’clock when he left home.
4. It would be about ten o’clock when she left home.
表示功能，意为“能，行”。惯用形式：will do/would do表示“解决问题”、“就行”。1. That will be all right.
2. Either pen will do.
3. It would not do to work too late.(工作太晚不行。)
用于否定句中，意为“不肯”、“不乐意”1.I won’t listen to your nonsense.
2.No matter what I said, he wouldn’t listen to me.
Will用于叙述真理时1.Oil will float on water.油能浮在水面上。
2.Man will die.人总会死的。
用于表示具有某种功能时1.The door will not open.门打不开。
2 The car will not start.车子启动不了。
特别说明：would与used to辨析
would可用来表示过去反复出现的动作，但不能表示过去存在的状态，所以我们不能说：“she would be a quiet girl.”
另外，would强调过去某种特定情况下的活动，是完全过去的事情，同现在没有联系。而used to则着眼于过去和现在的对比，隐含现在已不存在，动作或状态都可表示。Would可以表示不规则的习惯，used to则不可。如： He used to be a naughty boy and cause trouble.
I used to get up at six in the morning.
Sometimes she would take a walk in the neighboring woods.
In those days, whenever I had difficulties, I would go to Mr. Chen for help.
六．need和dare
情态动词用法例句
need用于表示“需要，必要”之意。做情态动词时，仅用于否定句和疑问句，(在肯定句中一般用must, have to, ought to, should代替。
)只有现在时， 1.—Need we leave soon?
—Yes, you must.(No, you needn't)
You needn’t come so early.
2. ---- Need I finish the work today?
---- Yes, you must. / No, you needn’t.
3.--Need I come? --Yes, you must. --我需要来吗? --需要。
4You needn´t telephone him now. 你现在不必打电话给他。
5.I don´t think you need worry. 我想你不必发愁。
6.She dare not go out alone at night. 她晚上不敢一个人出去。
7.How dare you say I´m unfair? 你竟敢说我不公平?
Not one of them dared mention this. 他们谁也不敢提这件事
做实义动词时，其变化与一般的实义动词相同，有人称、时态和数的变化，后接带to的不定式或者名词。,过去式用needed、did you need?和didn't need,肯定式用needs/needed/need,疑问式用do、does、did提问，否定式要在前面加don't、doesn't、didn't
(need doing = need to be done )表被动1. A job like nursing needs patience and understanding.(need+名词，need understanding=need to be understood,需要被理解)
2.He needs to see a doctor.(need to do)
3.Do you still need volunteers to help clean up after the party?(need somebody to do something)
4.They didn't need to start so early.(do not need to do)
5.You don´t need to do it yourself. 你不必亲自做这件事。
6.We need to tell them the news. 我们需要把这消息告诉他们。
7.The table needs painting (to be painted.). 桌子需要油漆一下。
8.We should dare to give our own opinion. 我们要敢于提出自己的观点。
9.He did not dare (to) look up. 他不敢抬头看。
10..I dare day he´ll come again. 我想他会再来的。
dare用于表示“敢于”之意。做情态动词，没有人称和数的变化，主要用于否定句、疑问句和条件状语从句中。过去式形式为dared。
1.—Dare you tell her the truth?
—Yes, I dare. /No, I daren’t.
3. How dare you accuse me of lying!
4. He daren’t admit this.
5. How dare you say I’m unfair?
6. He daren’t speak English before such a crowd, dare he?
7. If we dared not go there that day， we couldn’t get the beautiful flowers.
用作实义动词时，其变化与一般的实义动词相同。在肯定句中，dare后接带to的不定式;否定句中，dare后既可接带to的不定式，也可接不带to的不定式。1. Only a few journalists dared to cover the story.
2. He doesn’t dare (to) go there alone.
3. Don’t you dare (to) touch it?
4.dare to swim across this river.
5. He doesn’t dare (to) answer.
6. He needs to finish his homework today.
7.I dare to swim across this river.
8.He does not dare (to) answer.
9 .Don't you dare (to) touch it!
10.I wondered he dare (to) say that.
11. He needs to finish it this evening.
七．ought的用法：
情态动词 用法 例句
ought to do表示“应该”之意1. You ought to take care of him.
2. —Ought I go now?
—Yes, you ought to. /No, you oughtn’t to.
3You ought to bring the child here.
表示推测。注意与must表示推测是的区别1. He must be home by now. (断定他已到家)
2. He ought to be home by now. (不十分肯定)
3. This is where the oil must be. (比较直率)
4. This is where the oil ought to be. (比较含蓄)
had bette表示"最好"
had better do sth
had better not do sth
It is pretty cold. You'd better put on my coat.
She'd better not play with the dog.
would rather
would rather do
would rather not do
would rather… than… 宁愿……而不愿。
would sooner,
had rather
had sooner表示"宁愿,宁可"If I have a choice, I had sooner not continue my studies at this school.
I would rather stay here than go home. = I would stay here rather than go home.
说明：should与ought to表示“应该”时的区别
should 表示自己的主观看法，
ought to的语气中，含有“按道理应该……”之意。(客观推测)，若要反映客观情况或涉及法律义务和规定，一般用ought to。ought to表示义务或责任，比should语气重。
must(主观推测)。如：
1.You should help them with their work.
2.You are his father. You ought to get him to receive good education.
3.He must be home by now.
4.He ought to/should be home by now.
5.This is where the oil must be.
6.This is where the oil ought to/should be.
7.I should help her because she is in trouble.
8.You ought to take care of the baby.
2) 表示劝告、建议和命令。should, ought to可通用，但在疑问句中常用should。
1. You should / ought to go to class right away.
2. Should I open the window?
八．“情态动词+have done ” 用法
情态动词+have done用法例句
must have done表示主观上对过去已经发生的行为进行推测，意为“想必，准是，一定做了某事”肯定句中。否定句用can 代替must1. She must have gone through a lot.
2. He must have visited the White House during his stay in the United States.
3.Linda has gone to work, but her bicycle is still here.
---She must have gone by bus.
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。1. You may have learnt the news.
2. He may not have heard his name called.
3. Sorry I’m late. I might have turned off the alarm clock and gone back to sleep again.
can…have done
cannot have done表示对过去发生的行为的怀疑和不肯定，通常用在否定句和疑问句中。(can换成could时语气委婉)
否定句表示：过去一定不。。。1. Where can she have gone?
2. Could he have done such a foolish thing?
3. The boy can’t have finished reading the book so soon because it is difficult even to an adult.
could have done可用于肯定句中，表示“可能已经……”之意，几乎等于may/might have done。后者更委婉一些。此外，还可以表示过去能做而没做的事，有一种对过去为付诸实施的事情的惋惜。
或”过去可能。。。
或本来能。。。而实际没有
1. He could have killed himself driving at a dangerous speed.
2. You could have been more considerate.
3. You could have done better, but you were too careless.
4. She could have been his wife.
她以前可能是他的妻子。
她本应该是他的妻子。
might have done表示“本来可能……，但实际上没有发生的事情”。另外，还可以表示“本来应该或可以做某事”之意，含有轻微的责备语气。1. You should not swim in that sea. You might have been eaten by a shark.
2. He might have given him more help, thought he was busy.
should/ought to have done用于肯定句时，表示本该做某事，而实际上未做;用于否定句时，则表示不该做的事反而做了。1. He should have known that the police would never allow this sort of thing.
2. You shouldn’t have done it so carelessly.
3. You ought to have returned the book earlier.
4. You ought not to have refused his offer.
5. 5.She should have finished it.
6. 6.I should have helped her, but I never could.
7. 7. You should have started earlier.
8. You ought not to have taken the book out of the reading-room.
needn’t have done表示做了本来不必去做的事。注意：didn’t need to do表示“没必要做而实际上也没有做某事”1.You needn’t have watered the plants, for it is going to rain.
2.I didn’t need to buy the dictionary. I had a copy at home.
3.You needn't have waited for me.
had better have done用于事后的建议，含轻微责备的口吻，意为“当时最好做了某事”，其否定式had better not have done表示相反的含义。1.You had better have started earlier.
2.You had better not have scolded her.
would rather have done表示“当时宁愿做了某事”，其否定式would rather not have done表示相反的含义，两者都表示“后悔”之意。1. 1.I would rather have taken his advice.
2. 2.I would rather not have told him the truth.
must to have been doing等
表示对过去某时正发生的事情的推测
情态动词后跟进行式，表示“想必正在……”，“可能正在……”，“应当正在”等意。
1--Why didn't you answer my phone call?
---Well, I must have been sleeping, so I didn't hear it.
2. It´s twelve o´clock. They must be having lunch. 现在是十二点。他们一定正在吃饭。
3.They may be discussing this problem. 他们可能正在论讨这个问题。
4.He can´t be telling the truth. 他说的不可能是真话。
5.She shouldn´t be working like that. She´s still so weak. 她不应当那样干，她身体仍那么虚。
n 情态动词表示猜测
肯定：must>should>could>may>might
n 否定：can’t>shouldn’t>couldn’t>may not>
n 表示要求，命令时，语气由 should(应该)、had better最好)、must(必须)渐强。
必须掌握情态动词表示推测语气时的反意疑问句。例如：
The road is wet. It must have rained, hasn’t it?
The road is wet. It must have rained last night, didn’t it? (多了过去时的时间状语)
I met him on his way home. He can’t be in the library now, isn’t he?
The coat is too close to the fire. It might get burnt, doesn’t it?
情态动词的基本用法归纳
情态动词有can (could), may (might), must, have to, shall (should, will (would), dare (dared), need (needed), ought to等。 情态动词无人称和数的变化;不能单独使用，必须与其后的动词原形构成谓语。
一、 can, could
1) 表示能力(体力、知识、技能)。
Can you lift this heavy box?(体力)
Mary can speak three languages.(知识)
Can you skate?(技能)
此时可用be able to代替。Can只有一般现在时和一般过去式;而be able to则有更多的时态。
I’ll not be able to come this afternoon.
当表示“经过努力才得以做成功某事”时应用be able to，不能用Can。如：
He was able to go to the party yesterday evening in spite of the heavy rain.
2) 表示请求和允许。
-----Can I go now?
----- Yes, you can. / No, you can’t.
此时可与may互换。在疑问句中还可用could,might代替，不是过去式，只是语气更委婉，不能用于肯定句和答语中。
---- Could I come to see you tomorrow?
---- Yes, you can. ( No, I’m afraid not. )
3) 表示客观可能性(客观原因形成的能力)。
They’ve changed the timetable, so we can go by bus instead.
This hall can hold 500 people at least.
4) 表示推测(惊讶、怀疑、不相信的态度)，用于疑问句、否定句和感叹句中。
Can this be true?
This can’t be done by him.
How can this be true?
二、 may, might
1) 表示请求和允许。might比 may语气更委婉，而不是过去式。否定回答时可用can’t或mustn’t，表示“不可以，禁止”。
----Might/ May I smoke in this room?
---- No, you mustn’t.
---- May/Might I take this book out of the room?
---- Yes, you can. (No, you can’t / mustn’t. )
用May I...?征徇对方许可时比较正式和客气，而用Can I...?在口语中更常见。
2)用于祈使句，表示祝愿。
May you succeed!
3) 表示推测、可能性(不用于疑问句)。
might不是过去式，它所表示的可能性比may小。
1.He may /might be very busy now.
2.Your mother may /might not know the truth.
三、 must, have to
1) 表示必须、必要。
You must come in time.
在回答引出的问句时，如果是否定的，不能用mustn’t(禁止，不准)，而用needn’t, don’t have to(不必).
---- Must we hand in our exercise books today?
---- Yes, you must.
---- No, you don’t have to / you needn’t.
2) must是说话人的主观看法， 而have to则强调客观需要。Must只有一般现在时， have to 有更多的时态形式。
1. he play isn’t interesting, I really must go now.
2. I had to work when I was your age.
3) 表示推测、可能性(只用于肯定的陈述句)
1. You’re Tom’s good friend, so you must know what he likes best.
2. Your mother must be waiting for you now.
四、 dare, need
1) dare作情态动词用时, 常用于疑问句、否定句和条件从句中, 过去式形式为dared。
1. How dare you say I’m unfair?
2. He daren’t speak English before such a crowd, dare he?
3. If we dared not go there that day， we couldn’t get the beautiful flowers.
2) need 作情态动词用时, 常用于疑问句、否定句。在肯定句中一般用must, have to, ought to, should代替。
1.You needn’t come so early.
2. ---- Need I finish the work today?
---- Yes, you must. / No, you needn’t.
3) dare和 need作实义动词用时， 有人称、时态和数的变化。在肯定句中，dare后面常接带to的不定式。在疑问句和否定句中，dare后面可接带to或不带to的不定式。而need后面只能接带to的不定式。
1. I dare to swim across this river.
2. He doesn’t dare (to) answer.
3. He needs to finish his homework today.
五、 shall, should
1) shall 用于第一人称，征求对方的意见。
What shall we do this evening?
2) shall 用于第二、三人称，表示说话人给对方的命令、警告、允诺或威胁。
1. You shall fail if you don’t work hard.(警告)
2. He shall have the book when I finish it.(允诺)
3. He shall be punished.(威胁)
六、 will, would
1) 表示请求、建议等，would更委婉。
Will / Would you pass me the ball, please?
2) 表示意志、愿望和决心。
1. I will never do that again.
2. They asked him if he would go abroad.
3) would表示过去反复发生的动作或某种倾向。would表示过去习惯时比used to正式，且没有“现已无此习惯”的含义。
1. During the vacation, he would visit me every other day.
2. The wound would not heal.
4) 表示估计和猜想。
It would be about ten o’clock when she left home.
七、 should, ought to
1) should, ought to表示“应该”，ought to表示义务或责任，比should语气重。
1. I should help her because she is in trouble.
2. You ought to take care of the baby.
2) 表示劝告、建议和命令。should, ought to可通用，但在疑问句中常用should。
1. You should / ought to go to class right away.
2. Should I open the window?
3) 表示推测
should , ought to (客观推测), must(主观推测)。
1.He must be home by now. (断定他已到家)
2.He ought to/should be home by now.(不太肯定)
3. This is where the oil must be.(直爽)
4. This is where the oil ought to/should be.(含蓄)
八、 情态动词+不定式完成式（have done）
1) can / could + have done在肯定句中表示“本来可以做而实际上能做某事”，是虚拟语气;在疑问句或否定句中表示对过去行为的怀疑或不肯定, 表示推测。
1. You could have done better, but you didn’t try your best. (虚拟语气)
2. He can’t have been to that town.(推测)
3. Can he have got the book?(推测)
2) may / might +不定式完成式(have done)
表示对过去行为的推测。不能用于疑问句中，没有虚拟语气的用法。Might所表示的可能性比may小。
1. He may not have finished the work .
2. If we had taken the other road, we might have arrived earlier.
3)must +不定式完成式(have done)
用于肯定句中，表示对过去行为的推测。意为“一定、想必”。其疑问、否定形式用can，can’t代替。参看1) can / could + have done表示推测。
1. You must have seen the film Titanic.
2. He must have been to Shanghai.
4)should +不定式完成式(have done)
用于肯定句中，表示对过去行为的推测。
He should have finished the work by now。
表示“本应该做而实际上没有做某事”，其否定式表示某种行为本不该发生却发生了。可以与ought to +不定式完成式(have done)互换。
1. You ought to / should have helped him. (but you didn’t.)
2. She shouldn’t have taken away my measuring tape, for I wanted to use it.
5) needn’t +不定式完成式(have done)
表示“本来不必做而实际上做了某事”。
You needn’t have watered the flowers, for it is going to rain.
6) will +不定式完成式(have done)
主要用于第二、三人称，表示对已完成的动作或事态的推测。
He will have arrived by now.
