情态动词

课件60张PPT。情态动词


语法特征
情态动词，在英文中主要用来表示说话人的看法、态度等。它很接近中文里的能愿动词。从用法上来说，它有这样几个特点：
1）各个情态动词自身都有一定的词义。
2）不能在句中独立担当谓语，也没有非谓语形式。
3）情态动词在句中不受任何人称,数变化的影响。
4) 情态动词后接的不定式（除ought外）都不带to ，即接动词原形。
英文中的情态动词主要有：can , could ; may , might ; must ; ought ; need ; dare , dared ，另外，shall , will , should , would在一定的场合也可用作情态动词。二 情态动词的用法
1 can 的用法
1 表能力
(1）can　could 表示能力；可能 (过去时用could),
只用于现在式和过去式(could)。be able to可以用于各种时态。
　如：They ___________tell you the news soon.
A. will be able to B can C could

The boy __________ play the piano very well when he was seven .
A. will be able to B can C could (2) was were able to 和could 在表示能力时可以替换；当表示成功地做了某事时，只能用was/were able to，相当于manage to 或succeeded in . 不能用could。
He was able to flee Europe before the war broke out.
= __________________________________________
=_________________________________________
注意：在否定句中，两者可以互换。
如：----I wonder why she hasn’t turned up yet .
----Perhaps she______________get away from
her work .
A wasn’t able to B couldn’t C can’t D is able to He managed to flee Europe before the war broke out.He succeeded in fleeing Europe before the war broke out.(3) 助动词后只用be able to
They will ____________ tell you the news soon. 他很快就能告诉你消息了。
(4) 情态动词后只用be able to 。
They may _____________ do it .be able to be able to 2 表示许可，允许，在疑问句中表示请求许可，在否定句中表示不许。此时代替更为正式的May .
------____________I come in ?
A May B Can
You ______smoke in non-smoking sections in public places , but you can in smoking-sections .
The teacher said that we _________ play foot ball on the playground .
注意：could在表示提出请求时和推测时，不表示时态。
　　 --- Could I have the television on?
　　 --- Yes, you ________.
----No, you ________.
（注意在回答中不可用could）can’tcouldn’tcancan’t3表示推测或怀疑，强周客观可能性“可能，会”多用于疑问句和否定句中，表示推测时可用现在时，进行时，完成时。
句子翻译：
他会是谁呢？________________________________________
他不可能正在等你。 ___________________________________
他不可能已独自去那里了。 ___________________________________Who can he be ?He can’t be waiting for you . He can’t have gone there along . 2 May 的用法
1） 表示允许或请求；口语中常可与can替换。
如：你现在可以走了。__________________________
表示没有把握的推测；”或许，可能”表示一件事情或许会发生，只用在陈述句中。
如：他可能来，但我认为他不会来。______________________________________
注意： might 表示推测时，不表示时态。只是可能性比may 小。　
He might be at home.You may go now .He may come, but I don’t think he will .
典型例题
　Peter ___come with us tonight, but he isn't very sure yet.
　 A. must　　B. may　 C. can　 D. will3 比较have to和must
1)　两词都是'必须'的意思，have to 表示客观的需要， must 表示说话人主观上的看法，既主观上的必要。
如：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)
_________________________________________
他说他们必须努力工作。（主观上要做这件事）
________________________________________
比较：I must leave now .(主观)
I ‘m afraid you’ll have to leave now , it’s a rule of the hospital .（客观）My brother is badly ill now , so I have to send for a doctor at midnight . He said they must work hard . 2)　have to有人称、数、时态的变化，而must只有一种形式。
He had to look after his sister yesterday.
3） 在否定结构中： don't have to　 表示"不必"
　　　　　　　　　　mustn‘t　　表示“禁止”，
　　你不一定要把此事告诉他。__________________________________________
　　你一定不要把这件事告诉他。 _______________________________________You don’t have to tell him about it .You mustn’t tell him about it .4在回答带有must 的问句时，否定结构不用mustn’t 而用needn’t don’t have to .
---Must I go home ?
---Yes , ________
---No ________
5 表示偏偏，干嘛，（指做令人不愉快的事情）
The car must break down just when we were about to start off .

Must you shout so loudly ?mustneedn’t / don’t have to . ( 干嘛 ) ( 偏偏 )6 must表示推测
　1) must用在肯定句中表示较有把握的推测，意为"一定"。
　2) must表对现在的状态或现在正发生的事情的推测时， must 后面通常接系动词be 的原形或行为动词的进行式。
你辛苦干一整天，一定累了。（对现在情况的推测判断）
____________________________________________
他一定在办公室工作呢。
____________________________________________
　比较：
　　　 He must be staying there.　 　　　
He must stay there. 　
You’ve worked all day long so you must be tired . He must be working in his office .他现在肯定呆在那里他必须呆在那。3) must 表示对已发生的事情的推测时，must 要接完成式。
我刚才没有听到电话，我想必是睡着了。
__________________________________________
　4) must表示对过去某时正发生的事情的推测，must 后面要接动词的完成进行式。
　　---Why didn't you answer my phone call?
　　---Well, I _________________,(sleep) so I didn't hear it.I did not hear the phone . I must have slept .must have been sleeping .5) 否定推测用can‘t。
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。 Shall
1)用于二、三人称的疑问句中，表示愿意，征询听话人是否愿意。
Shall you go with me ? 你愿意跟我一起去吗？
Shall he come to Beijing tomorrow ?
他明天去北京行吗？ 2)用于征求对方的意见和指示，用在一，三人称的疑问句中。
Shall I turn on the light ?
Shall he come to see you ?
_________________________________________
注： Shall +第三人称主格+do sth ====Do you want +第三人称宾格+to do sth .=Do you want him to see you ?5 should 用法
Should不是一个单独意义的情态动词，它只是shall 的过去式。
1 表示劝告，建议常作应该，应当之义，与ought to 有时可以互换，ought to更注意一些责任义务。
You should do it by yourself .
2 表示按常理进行推测，预测其可能性，译为“应该，可能”
He should be in his office now .
3 表示委婉地，谦逊地提出意见或建议。
I should think you are right .4 should用于某些从句中表虚拟语气。
1）用于表示建议，命令的从句中，表示建议，命令的动词有suggest advice demand require request desire ask insist 等词的宾语从句的谓语动词用should+动词原形。并可以省略。
He suggested that I (should) do so.
2)用在suggestion wish requirement instruction order plan idea 等词后的表语从句或同位语从句中。
It is my wish that you should do so .3)用于一些如it is demand /desired /insisted /ordered /suggested /necessary /important/that ….等结构的主语从句中。如
It is demanded that we get everything ready by the end of the week .
4) 表示惊奇，怀疑，不满等情绪，译为“竟然”
It’s a pity that he should be so careless . 6 will
1)表示意志和决心，用于各种人称。
I’ll do my best .
2)表示各种倾向或习惯动作。
Fish will die out of water .
--Who can close the door ?
--I will (I’ll do it )
注本句不能用be going to /be to do 结构，因为本句不表计划打算，只是一个反射性动作。3）也表示一种揣想推测，用于二三人称。
They will have arrived by now .他们大概已经到了。
4）用于疑问句表示请求，邀请。
Will you give me a piece of paper ?
5)有时表示难免 毕竟。
Boys will be boys . 男孩毕竟是男孩。
Accident will happen . 事故难免会发生。7 would
would 是will的过去式，would +v 构成过去将来时，除此之外，是单独的情态动词。
1 表示过去时间的“意志，愿望和决心”
I told him that I would go along with him .
2 委婉提出请求，建议或看法，语气比will委婉，肯定答语用will .
Would you help him ? Yes , I will .
3 表示过去的习惯动作和过去的某种倾向。
When he was a child he would (used to )play football .
Would 和 used to 的区别。
1 used to 主要用于今昔习惯的对比，表明过去如何，现在已不再如此了。而would 不能用于今昔习惯的对比。
2 used to 用于表示过去的习惯或过去一贯存在的情况状态，而would只能表示过去重复的动作，不能表示情况或状态。如
There used to be a house here . 不能用would 这里是表状态。
3 used to 不可接时间状语，而would只谈过去，与现在无关，因此句中常有时间状语。（always every day 或表示时间的上下文。）8 Need 的用法
1） need 的意思是“”需要，既是行为动词，又是情态动词。

作形为动词时，他具有一般动词的各种形式，（need needs needed needing）,与助动词（do does did ）连用构成疑问句和否定句，后面接名词或动词不定式作宾语。

作为情态动词，只有一种形式，没有人称和数的变化，后接动词原形，与not 连用时构need not的否定式，疑问句把need提前。 1)I need a new computer .
2)Your room need painting
3)He doesn’t need to work late into the night .
4)I need to get a new car .
5)Need he work so late ?
yes, he must no , he needn’t .
6)you needn’t walk that fast , need you?
你不必走那么快，是吗？实义动词情态动词实义动词实义动词实义动词情态动词注意1：
need 的被动含义：need, want, require, worth（形容词）后面接doing也可以表示被动：　need doing = need to be done
注意2：
need 作情态动词不用在肯定句中，只用于疑问句和否定句中， 9 dare的用法
1 它既可以作形为动词又可以作情态动词，作情态动词时，主要用于疑问句，否定句及条件句中，陈述句中很少使用但（I dare say ）除外。没人称和数的变化，但有时态变化，过去时为dared. 否定式为daren’t .
How dare you say I’m unfair ?
He dare not speak English before such a crowd , dare he ?情态动词情态动词9 作形为动词时，有时态，人称和数的变化，所不同的是，作形为动词时，在肯定句中，其后常接带to的动词不定式，但在否定句和疑问句中，其后的to 可省可不省。如：
I dare to swim across this river .
He does not dare (to) answer
Don’t you dare (to )touch it ?10 含有情态动词的反意疑问句构成反意问句时，常用情态动词。
She will come , won’t she?
1）谓语动词是“ought to +动词原形”疑问部分用ought , ought not , shouldn’t +主语代词。
He ought to be punished ,___________
2) 当陈述部分是dare need 时，分情况而定。
如：They need to do it ,
You daren’t come , oughtn’t he ?don’t they ?dare you ?3) must 表推测时， 疑问部分应该根据其后的谓语动词来确定。(注意：当must have done结构中有表示过去的时间状语时，不用haven’t 而用didn’t)
如：you must be Mr Li , _________
you must have finished it , __________
She must have read the book yesterday ,_________
注：must 表示禁止时，附加部分最好不重复使用must 而用may
You mustn’t walk on grass , _____________
注：could表示推测时，反意疑问句附加部分构成与must一致。
She couldn’t have finished it yesterday, ___________aren’t you ?haven’t you ?didn’t she ?did she ?maymust you ?11 表示推测的用法
　can, could, may, might, must 皆可表示推测，其用法如下：
1）情态动词+动词原形。
　　表示对现在或将来的情况的推测，此时动词通常为系动词。
　　I don't know where she is, she may be in Wuhan.
2）情态动词+动词现在进行时。
　　表示对现在或将来正在进行的情况进行推测。
　　At this moment, our teacher must be correcting our exam papers.
　　3）情态动词+动词完成时。
　　表示对过去情况的推测。
　　The road is wet. It must have rained last night.
　　地是湿的，昨天晚上一定下雨了。4）情态动词+动词的现在完成进行时。
　　表示对过去正在发生事情的推测。
　　Your mother must have been looking for you.
　　你妈妈一定一直在找你。
5）推测的否定形式，疑问形式用can't, couldn't表示。
　　Mike can't have found his car, for he came to work by bus this morning.
　迈克一定还没有找回他的车，因为早上他是坐公共汽车来上班的。
　注意：could, might表示推测时不表示时态，其推测的程度不如can, may。 12 情态动词+ have +过去分词
may(might) have + done sth,
can (could) have + done sth　
表示过去，推测过去时间里可能发生的事情。
　　Philip may (might) have been hurt seriously in the car accident.
　　Philip can (could) have been hurt seriously in the car accident.2)　must have +done sth，对过去时间里可能发生的事情的推测，语气较强，具有“肯定”，“谅必”的意思。
　---Linda has gone to work, but her bicycle is still here.
　---She must have gone by bus.3) ought to have done sth, should have done sth
　　本应该做某事，而事实上并没有做。否定句表示“不该做某事而做了”。
　　You ought to (should) have been more careful in this experiment.
　　He ought not to have thrown the old clothes away.（事实上已扔了。）
　　ought to 在语气上比should 要强。8 should 和ought to
　　should 和ought to 都为"应该"的意思，可用于各种人称。
　　---Ought he to go?
　　---Yes. I think he ought to.
　　
表示要求，命令时，语气由 should（应该）、had better最好）、must（必须）渐强。 13 情态动词的回答方式
　　 问句　　　肯定回答　　　　否定回答
Need you…?　Yes, I must.　　 No,I needn't
Must you…?　 Yes,you must. 　Needn’t/don't have to. 典型例题
1）---Could I borrow your dictionary?
　　---Yes, of course, you____.　
　 A. might　B. will　 C. can　 D. should
　 答案C. could表示委婉的语气，并不为时态。答语中of course，表示肯定的语气，允许某人做某事时，用can和 may来表达，不能用could或might。复习： will 与you连用，用来提出要求或下命令。should与you 连用，用来提出劝告。2）---Shall I tell John about it?
　　---No, you ___. I've told him already.　　
　A. needn't B. wouldn'tC. mustn't D. shouldn't
　 答案A。needn‘t 不必，不用。 wouldn’t 将不, 不会的。 mustn‘t 禁止、不能。 shouldn’t　不应该。本题为不需要，不必的意思，应用needn‘t。
3）---Don't forget to come to my birthday party tomorrow.
　　---______.
A. I don't　 B.　I won't　 C. I can't　D. I haven't
　　
答案B.　will既可当作情态动词，表请求、建议、也可作为实义动词表“意愿、意志、决心”，本题表示决心，选B。 14 区别微妙的情态动词练习
情态动词在近年来的考试题中的难度日渐加大，不仅是由于情态动词表示说话人的语气和心态等，而且这些往往是需用心体会而得的。由于语气的暗示在题目中变得更隐蔽，语气的变化更微妙，因而更综合化了。
●难点磁场
1.(★★★★★)I didn’t hear the phone I________ asleep.
A.must be B.must have been
C.should be D.should have been
2.(★★★★★)We ________ last night,but we went to the concert instead.
A.must have studied B.might study
C.should have studied D.would study
3.(★★★★★)John,you________ play with the knife,you________hurt yourself.
A.won’t;can’t B.mustn’t;may
C.shouldn’t;must D.can’t;shouldn’t4.(★★★★★)—Shall I call a doctor for you?
— ________.I will be better soon.
A.Yes,you may B.No,you mustn’t
C.No,you needn’t D.I’d rather not
5.(★★★★)—Would you like to go shopping with me tonight?
—________.
A.I’d love so B.I’ll like to
C.I would like that D.I’d love to
6.(★★★★★)He________ you more help,even though he was very busy.
A.might have given B.might
C.may have given D.may give
7.(★★★★★)Noise________ harmful in China.
A.didn’t use to be considered B.usedn’t to consider
C.didn’t use to consider D.isn’t used to be considered●案例探究
1.—Will you stay for lunch?
—Sorry,________ my brother is coming to see me.
A.I mustn’t B.I can’t
C.I needn’t D.I won’t
知识依托：mustn’t 不允许、禁止
can’t客观上不能办到
needn’t不需要
won’t不会，不愿意
答案：B
一、情态动词表推测
1. 肯定的推测一般用must, should, may（might）或could（不用can），其中，must的语气最强，译为“肯定”、“准是”、“想必是”；should的语气次之，译为“很可能”、“应该”，指按常理推测；may（might），could的语气最弱，译为“也许”、“可能”。①Helen _______ go on the trip with us but she isn’t quite sure yet. （2005年安徽卷）
A. shall B. must C. may D. can
②—I’ve taken someone else’s green sweater by mistake.
—It ___ Harry’s. He always wears green. （2005年广东卷）
A. has to be B. will be C. mustn’t be D. could be
③I have lost one of my gloves. I _______ it somewhere.（2005年北京春季卷）
A. must drop B. must have dropped
C. must be dropping D. must have been dropped
2. 否定推测分为两种情况：
1）语气不很肯定时，常用may not, might not或could not，译为“可能不”、“也许不”。

2）否定语气较强时，则用can’t，译为“根本不可能”、“想必不会”，表示惊异、怀疑的感彩。

1) —Do you know where David is? I couldn’t find him anywhere.
—Well. He ______ have gone far——his coat’s still here.（2005年湖北卷）
A. shouldn’t B. mustn’t C. can’t D. wouldn’t
2)— Isn’t that Ann’s husband over there?
— No, it _______ be him I’m sure he doesn’t wear glasses. （2004年全国卷Ⅰ）
A. can’t B. must not C. won’t D. may not 3. 疑问句中的推测，往往用can或could。

Mr. Bush is on time for everything. How ______ it be that he was late for the opening ceremony？（2001年上海春季卷）
A. can B. should C. may D. must
2. must用于疑问句，表示责备、抱怨的感彩，意思为“偏偏，偏要”；mustn’t表示禁止，是说话人强有力的劝告。
①John, look at the time. _______ you play the piano at such a late hour？ （2005年全国卷Ⅲ）
A. Must B. Can
C. May D. Need
②Tom, you leave all your clothes on the floor like this！ （2005年全国卷Ⅰ）
A. wouldn’t B. mustn’t
C. needn’t D. may not
3. needn’t表示“没有必要”。
— Lucy doesn’t mind lending you her dictionary.
— She ______. I’ve already borrowed one. （2005年湖南卷）
A. can’t B. mustn’t
C. needn’t D. shouldn’t
4. would表示过去反复发生的动作或某种倾向。
When he was there, he ___ go to that coffee shop at the corner after work every day.（1996年上海卷）
A. would B. should
C. had better D. might
5. 表示经过努力而成功的某一次动作，只能用was/were able to，而不能用could。
The fire spread through the hotel very quickly but everyone _____ get out. （1997年全国卷）
A. had to B. would
C. was able to D. could
6. 考查情态动词用作答语的情况
①—Write to me when you get home.
— _______. （2001年北京春季卷）
A. I must B. I should
C. I will D. I can
② — Could I call you by your first name？
—Yes, you ______. （1998年上海卷）
A. will B. could
C. may D. might
情态动词过关检测题
1. --- Tom graduated from college at a very young age.
--- Oh, he ______ have been a very smart boy then.
A. could B. should C. might D. must
2. --- I’ll tell Mary about her new job tomorrow.
--- You ______ her last week.
A. ought to tell B. would have told
C. must tell D. should have told
3. --- Excuse me, is this the right way to the Summer Palace?
--- Sorry, I am not sure. But it ______ be.
A. might B. will C. must D. can
4. I ______ pay Tracy a visit, but I am not sure whether I will have time this Sunday.
A. should B. might C. would D. could
5. I often see lights in that empty house. Do you think I ______ report it to the police?
A. should B. may C. will D. can
6. Mr White ____at 8:30 for the meeting, but he didn’t show up.
A. should have arrived B. should arrive
C. should have had arrived D. should be arriving
7. --- Isn’t that Ann’s husband over there?
--- No, it ______ be him---I’m sure he doesn’t wear glasses.
A. can’t B. must not C. won’t D. may not
18. You _____be tired --- you’ve only been working for an hour.
A. must not B. won’t C. can’t D. may not
9.“ ______ I hand in the paper this week?”
“ No, you ______. You _____ hand it in next week.
A. Must; needn’t; may B. will; mustn’t; ought to
C. Shall; can’t; have to D. Should; didn’t have to; can
10. There were already 4 people in the car but they managed to take John as well. It ______ a comfortable journey.
A. can’t be B. wouldn’t be
C. mustn’t have been C. couldn’t have been
11. It’s nearly eight o’clock. They ______ be here at any moment.
A. must B. can C. should D. need
12. “ ______ I take the magazine out of the reading room?” “ Sorry, you _____.”
A. May; mustn’t B. Must; can’t
C. will; didn’t have to C. Can; aren’t able to13. Let’s sing a song, ______ we?
A. will B. can’t C. shall D. do
14. “________ I have a glass of beer?” “ No, I’m afraid you ________.”
A Can’t; can’t B. Could; won’t
C. May; daren’t D. Shall; may
15.“ Isn’t that Tom playing basketball?” “ It ______ be; he fell off the ladder yesterday and got badly hurt.”
mustn’t B. would rather not
C. couldn’t D. wouldn’t
16. “ Need he go?” “ Yes, he ______.”
A. need B. can C. may D. must
17. Tell me how you work out the answer, _______ you?
A. can B. will C. don’t D. shan’t