(共20张PPT)
语法 ：情态动词
I 情态动词的定义
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。
情态动词数量不多，但用途广泛，主要有： can (could), may (might), must, need, ought to, dare (dared), shall (should), will (would) .
II 情态动词的位置
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， 情态动词放在主语之前。
I can see e 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 你要什么？
How dare you treat us like that! 你怎么敢那样对待我们!
Ⅲ 情态动词的语法特征
1） 情态动词不能表示正在发生或已经发生的事情，只表示期待或估计某事的发生。
2） 情态动词除ought 和have 外，后面只能接动词原形。
3） 情态动词没有人称，数的变化，即情态动词第三人称单数不加-s。
4） 情态动词没有非谓语形式，即没有不定式，分词，等形式。
Ⅳ 情态动词的用法
情态动词 Modal Verbs
can和could
情态动词 用 法 例 句
can/could
1．“I don’t think Mike can type.” “Yes, he can.”
2．I can speak fluent English now , but I couldn’t last year.
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
Can we turn the air conditioner on
In soccer, you can’t touch the ball with your hands.
Could you have her call me back when she gets home, please
I wonder if I could just ask you to sign this.
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.
Can this be an excuse for not giving them help
This can’t be true.
How can you be so crazy.
1.表示能力
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。
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。
在肯定句中，表示客观可能性，，常用来说明人或事物的特征（译为“有时会”）。要表达具体某事实际发生的可能性时，不用can，需用could，may，might。
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。
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.或者是you can’t)
2.表示推测时，could不是过去式，只是语气更委婉；若是推测已发生的事或过去的情况，用can/could have done
3.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 be 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。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.
4 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 May I come in and wait
——May I smoke here
——No, you mustn’t(或No, you’d better not.)
Might I borrow your pen
I wonder if I might speak to your son.
It may rain this afternoon.
She might come to join us this afternoon.
I suppose he might have missed the train.
May you succeed.
May you live happily!
May she rest in peace.愿她安息。
There is nothing to do, so I may as well go to bed.
You may as well tell us now, we’ll find out sooner or later.
I suppose we might as well go home.
表示允许、许可。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。
在表示请求、允许时，might比may语气更委婉些。用May I征询对方许可在文体上比较正式，在日常用语中，用Can I征询对方意见更为常见。
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。
may用于祈使句表示祝愿
惯用句式：
“may as well或might(just)as well+动词原形”意为“最好，满可以，倒不如”，相当于“had better.
1.A computer ____ think for itself; it must be told what to do.
A. can’t B. couldn’t C. may not D. might not
I thought you ________ like something to read, so I have brought you some books. A. may B. might C. could D. must
may, might, can, could
1. They (can/might) ___________be away for the weekend but I’m not sure.
2. You (may/might) __________leave now if you wish.
3. (could/may) __________you open the window a bit, please
4. He (can/could) __________be from America, judging by his accent.
5. (may/can) ___________you swim
6. Listen, please. You (may not/might not) _________________ speak during this exam.
might
表示猜测
may
表示许可
could
表示请求
could
表示猜测
can
表示能力
may not
表示不允许
may, might, can, could
7. They (can not/may not) _______________ still be out, the light is on in the house.
8. You (couldn’t/might not) _________________ smoke on the bus.
9. With luck, tomorrow (can/could) __________be a cooler day.
10. You (can/might) ___________ be right, but I’m going back to check it.
表示许可
couldn’t
could
表示猜测
can not
表示猜测(不可能)
might
表示猜测
三．must和have to
情态动词 用法 例句
must You must come to school on time.
Everybody must obey the law.
You mustn’t drive so fast in the street.
We mustn’t waste any more time.
1．—Must I come back before ten
—Yes，you must.
----No, you needn’t(No, you don’t have to)
It must be my mother.
You must be hungry after a walk.
There must be a hole in the wall.
have to The film is not interesting. I really must go now.
I have to go now, because my mother is in hospital.
1．I had to work hard when I was your age.
2．I will have to learn how to use acomputer.
3．In order to take the exam, we’ll have to finish the whole book by the end of this month .
You mustn’t go there.
You don’t have to go there.
表示“必须，应该”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
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
表示有把握的推测，意为“一定、准是、相必”，只用于肯定句中
“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。
must只有一种形式，即现在式与过去式都是一种形式，而have to则涉及各种人称、时态等方面的变化形式。
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。
注意：表示”偏要，硬要做某事
-how old are you, madam
-if you must know, I’m twice my son’s age.
如果你非得知道，是我儿子年龄的两倍
四．shall和should
情态动词 用法 例句
shall Shall I open the window
Shall we say 6 o’clock, then
Shall he come to see you
Don’t worry, you shall get the answer this afternoon
He shall be sorry for it one day, I tell you. （
You shall do as I say. If you children don’t do as I tell you, you shall not go to the party.
The Persons under 18 shall not be employed in night work．不满十八岁的人不得雇佣干夜间工作。
That day shall come
Candidates shall remain in their seats until all the papers have been collected. 试卷完全收回后，应试人才能离开座位。
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,其意为“要不要”、“…好吗”：
1 用于第二、三人称陈述句中，表示说话人给对方的命令、警告、允诺、威胁、命令、规定、必然性等
2表示强制，用于法令、条约、规章中，意为“必须，应该”。
.(允诺)
警告）
(命令)
(威胁)
(表规定)
(表必然性)
should What should I do
Should I trust him
You should read his new book.
It should be a nice day tomorrow.
It ‘s nearly 7 o’clock .Jack should speak in such a way.
He should be around sixty years old.
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)
Should I be free tomorrow, I’ll come. (万一我明天有时间，我就过来)
If things should change suddenly, please let me know. (万一情况突变，请通知我)
It’s strange that he should come so late.
I’m sorry that this should have happened.
I’m surprised that he should say so. Why should anyone want to marry Tony
Don’t ask me. How should I know
表示劝告或建议，意为“应该”
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，理应” 大概。
【注】should表示推断时，语气较肯定，通常是指非常可能的事(因为暗示有一定的事实依据或合乎常理)，
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
1should表示意外或惊讶
2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. It’s nearly seven o’clock. Jack _____ be here at any moment.
A. must B. need C. should D. can
2. Johnny, 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’t
3.Our house is on the top of the hill, so in summer the wind _____ be pretty cold.
A. must B. can C. ought to D. need
4. Professor Smith, many students want to see you. __________ they wait here or outside
A. Do B. Shall C. Will D. Would
五．will和would
情态动词 用法 例句
will/would He is the man who will go his own way.
They said they would meet us at 10:30 at the station.
Will you please take a message for him
Would you please tell me your telephone number
Fish will die without water.
People will talk. (人们总会说闲话。)
When we worked in the same office, we would often have coffee together.
These things will happen.
That will be the messenger ringing.
It would be about ten o’clock when he left home.
That will be all right.
Either pen will do.
It would not do to work too late.（工作太晚不行。）
1．I won’t listen to your nonsense.
2．No matter what I said, he wouldn’t listen to me.
用于表示意志或意愿或决心。will指现在，would指过去。
表示请求、建议等和you连用，用would比用will委婉、客气。
表示习惯或倾向，意为“总是，惯于”。will至现在，would指过去。
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。
表示功能，意为“能，行”。惯用形式：will do/would do表示“解决问题”、“就行”。
用于否定句中，意为“不肯”、“不乐意”
特别说明：would与used to辨析
1 He _____ be a naughty boy and cause trouble.
2 I ___________get up at six in the morning.
3 Sometimes she ______________take a walk in the neighboring woods.
4 In those days, whenever I had difficulties, I _________go to Mr. Chen for help.
used to
used to
would
would
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.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。
1. We __________ smoke here, because the worker is carrying some petrol.
2. It is dangerous. You __________ leave the room immediately.
3. He ___________ go hiking with friends at weekends when young.
4. Write to me when you get home.
---I ___________.
5. --Need I hand in my exercise book at once
--Yes, you__________.
6. You have been working all day. You __________ be very tired.
7. It is a long time since we met last time. You __________ come and see us more often.
8. Why don’t you try on this dress It _________ look nice on you.
will, would, shall, should, must:
mustn’t
should
would
will
must
must
should
will
表示禁止,不许可
表示建议,命令
表示过去习惯
表示意愿
表示必须
表示肯定猜测
表示建议
表示将会,一定会
六．need和dare
情态动词 用法 例句
need 1．—Need we leave soon
—Yes, you must.(No, you needn't, or don’t have to)
2．You needn't have hurried.
(=It was not necessary for you to hurry，but you did).你当时不必这么匆忙。
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．They didn't need to start so early.(do not need to do)
dare 1．—Dare you tell her the truth
—Yes, I dare. /No, I daren’t.
How dare you accuse me of lying!
He daren’t admit this.
Only a few journalists dared to cover the story.
He doesn’t dare (to) go there alone.
Don’t you dare (to) touch it
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，只有现在时，过去式要用needn't have，疑问式用need+人称 ,否定式用need not(即needn't），
做实义动词时，其变化与一般的实义动词相同，后接带to的不定式（need doing = need to be done ）, 疑问式，否定式要在前面加do的相应形式
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
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。
七．ought的用法：
情态动词 用法 例句
ought to do You ought to take care of him.
—Ought I to go now
—Yes, you ought to. /No, you oughtn’t to.
He must be home by now. (断定他已到家)
He ought to be home by now. (不十分肯定)
This is where the oil must be. (比较直率)
This is where the oil ought to be. (比较含蓄)
说明：should与ought to 表示“应该”时的区别
You____________ help them with their work.
You are his father. You ___________get him to receive good education.
表示“应该”之意
表示推测。注意与must表示推测是的区别
should
ought to
should 表示自己的主观看法，而ought to的语气中，含有“按道理应该……”之意。若要反映客观情况或涉及法律义务和规定，一般用ought to。
—Shall I go and buy more fruit for the party
—No, I have already bought 3 baskets. That _________ be enough.
A. can B. ought to C. may D. might
He used to teach in that university and I _________ ride past it on my way to work.
A. would B. could C. should D. might
—Would you be here to attend the English party this evening
—Yes, we _________.
A. shall B. would C. will D. must
八．“情态动词+have done”用法
情态动词+have done 用法 例句
must have done She must have gone through a lot.
He must have visited the White House during his stay in the United States.
may/might have done You may have learnt the news.
He may not have heard his name called.
Sorry I’m late. I might have turned off the alarm clock and gone back to sleep again.
can…have done
cannot have done Where can she have gone
Could he have done such a foolish thing
The boy can’t have finished reading the book so soon
could have done He could have killed himself driving at a dangerous speed.
You could have done better, but you were too careless.
might have done You should not swim in that sea. You might have been eaten by a shark.
He might have given him more help, thought he was busy.
表示对过去已经发生的行为进行肯定推测，意为“想必，准是，一定做了某事”只用于肯定句
表示对过去已发生行为的可能推测，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。
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）
可用于肯定句中，表示“可能已经……”之意，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。
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。
should/ought to have done He should have known that the police would never allow this sort of thing.
You ought not to have refused his offer.
needn’t have done You needn’t have watered the plants, for it is going to rain.
had better have done You had better have started earlier.
You had better not have scolded her.
would rather have done 1．I would rather have taken his advice.
2．I would rather not have told him the truth.
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。
表示做了本来不必去做的事。
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。
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。
1The thief ________ in from the kitchen window as the door was closed.
A. may climb B. must have climbed
C. could have climbedD. should have climbed
2—I posted the letter a week ago.
—Then they __________ the letter by now. It usually takes four days.
A. can have received B. must receive
C. should receive D. ought to have receive
3.There were already five people in the car, but they managed to take me as well.
— It __________ a comfortable journey.
A. can’t B. shouldn’t be C. must have been D. couldn’t have been
1.---There were already five people in the car but they managed to take me as well.
---It ____a comfortable journey. ( )
A. can't be B. mustn't have been
C. shouldn't be D. couldn't have been
D
2.The fire spread through the hotel very quickly but everyone ___ get out. ( )
A. had to B. would
C. could D. was able to
D
3. Peter ___ come with us tonight, but he isn’t very sure.
must B. can C. may D. will
C
4. --- Could I call you by your first name --- Yes, you____.
A. will B. could C. may D. might
C
5. Sorry, I ’m late. I ___ have turned off the alarm clock and gone back to sleep again.
might B. should C. can D. will
A
6.--Excuse me, but I want to use your computer to type a report.
--You ____ have my computer if you don’t take care of it.
A. shan’t B. might not C. needn’t D. shouldn’t
A
7. ---When can I come for the photos I need them tomorrow afternoon.
---They _____be ready by 12 : 00 .
A. can B. should C. might D. need
B
8. With so much work on hand, you ____to see the game last night.
A. mustn’t go B. could have gone
C. shouldn’t go D. shouldn’t have gone
D
9.Johnny, you ______play with the knife, you ____hurt yourself. ( )
A. won't ; can't B. mustn't ; may
C. shouldn't ; must D. can't ; wouldn't
B
10. I missed the bus, so I ___ go home on foot.
A. must B. may C. can D. had to
D(共24张PPT)
Discovering
useful structures
--- Modal Verbs (I)
情态动词的语法特征
情态动词有一定的意义，表示或暗示某种情绪或
态度，表示可能、建议、愿望、必要、允许、能力等。
2. 情态动词没有人称和数的变化，即不随主语的不同而变化。
3. 情态动词不能独立使用，必须和实义动词一起构成谓语。
4. 情态动词除ought和have外，后面只能接不带to的 不定式。
5. 情态动词没有非谓语形式，即没有不定式、分词等形式。
must
表示必须， 多处于义务、责任或强制命令(must提问，否定回答用needn’t或don’t have to).
You must hand in your homework today.
(2) mustn’t 表示禁止。意思是“不许”、“不准”、“不可以”。
You mustn’t smoke here.
(3) 用于发生了某种于说话人的愿望相反、不受欢迎的事时，意思是“偏偏”、“偏要”。
Why must he do it that way
Why must it rain on Sunday
(4) 表示推测， 只能用于肯定句。
He must be reading novels now.
The road is wet. It must have rained last
night.
can /could
(1)表示能力
Can you speak Japanese
(2)表示推测时，只用在否定句或疑问句中。
He can’t be at home now.
(3) 表示允许(许可或请求许可）
You can go now, but he can’t.
(4) 表惊异、怀疑等
How can you be so rude
could可表示能力或可能性，多用于过去，也可指现在，通常表示虚拟或作为can的委婉形式。
can / could + have done在肯定句中表示“本来可以做而实际上没做某事” ；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。 You could have done better, but you didn’t try your best.
你本来可以做得更好，但你没努力。
He can’t have been to that town.
他不可能去过那个城。
may/might
(1)表示可能性，might比may可能性更小。
It may be true.
He might not come today.
(2) 表示请求、许可，多用于肯定和疑问句中
May I ask you a question
(3) 表示愿望
May you be happy all your life.
might 比 may 语气更委婉
may/might表示推测时，表示对现在或将来要发生的事情把握不大。
might/may have done表示对过去发生的动作进行的可能性推测。
He may have gone to the clinic.
他可能去医务室了。
He might have read about the news in the newspaper.
他可能已经从报纸上知道这个消息了。
will/would
表示意愿，will表示现在的意愿，would表示过去的意愿。
Go where you will.
She asked if I would go with them.
2. 表示征求意见或提出请求，主要用于第二人称的疑问句中，will和would均可用，would此时并不表过去，而表示委婉语气。
Would Sunday night suit you
Will / Would you please post the letter for me
3. 表示习惯和倾向性
will表示现在的习惯，would表示过去的习惯(=used to do)。
Oil will float on water.
When he was a child, he would often go skiing.
4. 表示推测 will用于谈论现在，would可用于谈论过去，也可用于谈论现在(语气较委婉)。 Ask him. He will know. Every family would have some sort of trouble. I thought you would have finished it by now.
shall / should
1.在陈述句中,shall用于二、三人称表示允诺、警告、命令、决心等。
You shall do as I say. (命令)
Nothing shall stop me doing it. (决心)
Tell him that he shall have the book tomorrow. (允诺)
2. shall在疑问句中, 用于一、三人称，用来表示请求或征求意见。
Shall I open the window for you？（征求意见）
Shall he fetch some water for you？（请求）
3. should常表示应当，意思和ought to相近，但语气较弱。
Young people should learn how to use computers.
5. should have done表示责备或批评,意为“本应该…但”
You should have told her the truth earlier.
She shouldn’t have left without saying a word.
4. should用于可能性推测时, 表“应该，很可能”
They left at 5:30. They should get there now.
1. Jack described his father, who ____ a brave boy many years ago, as a strong–willed man. （2010 安徽卷）
A. would be B. would have been
C. must be D. must have been
答案：D
解析：句意为“杰克把他的父亲描述为一个意志坚强的人，他的父亲多年前肯定很勇敢”用must have been表示对过去事情的肯定推测。
高考真题
2. You _____ buy a gift, but you can if you want to. （2010 湖南卷）
A. must B. mustn't
C. have to D. don't have to
答案：D
解析：don’t have to 意为“没有必要”，符合语境，句意为：“你没有必要买礼物，但如果你想买的话，你也可以买。”
3. I have told you the truth. ______ I keep
repeating it （2010 江西卷）
A. Must B. Can
C. May D. Will
答案：A
解析： must 必须, 一定 can 可以, 能够， may 也许，will 意愿, 倾向性动作。前半句说我告诉你事实了, 这里用的是现在完成时, 表示过去的动作对现在造成了影响, 既然我已经说了, 我还必须重复一遍吗？
4. I_______ have watched that movie —
it’ll give me horrible dreams. （2010山
东卷）
A. shouldn’t B. needn’t
C. couldn’t D. mustn’t
答案：A
解析：句意应为“我本来不应该看那部电影的----它会使我做噩梦的。”表示“本来不应该做而做了某事”用shouldn’t have done, 所以A项正确。
As he had heart attack, he was told that he
____ continue the work. A. needn't B. may not C. mustn't D. can't
2. An Englishman who ____ not speak Italian was once traveling in Italy.
A. must B. could C. may D. might
3. I ____ like to make a suggestion.
A. could B. would C. must D. might
4. I know things are hard with you, but you ____ try to get over the difficulties. A. can B. may C. must D. ought
C
C
B
B
Choose the best answers.
5. We hope that as many people as possible
_____ join us for the picnic tomorrow. A. may B. must C. should D. can 6. — I think I’ll give Bob a ring. —You _____. You haven’t been in touch
with him for ages. A. will B. may C. would D. should 7. — Could I have a word with you, Mum — Oh dear, if you ______. A. can B. must C. may D. should
D
D
B
8. It is usually warm in my hometown in March,
but it _____ be rather cold sometimes.
A. must B. can C. should D. would
9. You don’t have to know the name of the
author to find a book. You _____ find the
book by the title.
A. must B. need C. can D. would
10. Although this ____ sound like a simple task, great care is needed.
A. must B. may C. shall D. should
B
C
B
11. You ______ be hungry already — you had
lunch only two hours ago!
A. wouldn’t B. can’t
C. mustn’t D. needn’t
12. According to the air traffic rules, you ___
switch off your mobile phone before
boarding.
A. may B. can C. would D. should
13. She ______ have left school, for her bike is
still here.
A. can’t B. wouldn’t
C. shouldn’t D. mustn’t
B
D
A
Complete the following sentences using modal verbs.
You’ve been working all day. You ______ be very tired.
2. I wonder who that is. It _____ be Lisa. She’s in the library at this time.
3. It is a long time since we met last time. You _____ come and see us more often.
4. I haven’t decided where I’m going for my holidays. I _____ go to Australia.
must
can’t
should
may
5. My father’s birthday is coming. What
_____ I get him
6. Why don’t you try on this dress It _______
look nice on you.
7. --- Who was the man talking with your
teacher
--- I’m not sure. It ______ be her brother.
8. I don’t know when the guests be here. They
_________ arrive at any time.
will
shall
might
will / could
1. Finish the exercises in
Discovering Useful Structure.
2. Finish exercises in Using
Structures in Workbook.
Homework(共28张PPT)
热身导入
Can you list some modal verbs that you remembered
modal verbs
Can/could
May/might
Will/would
Shall/should
must
Ought to
Used to
dare
Be able to
need
Have to
情态动词的语法特征
1情态动词除ought to和used to外，后面只能接不带to的不定式。
2情态动词没有人称，数的变化，will can dare 除外。
3情态动词“时态”的形式并不是区分时间的主要标准
自主学习
自主学习
Read page7-8 and learn “can could be able to”
归纳总结
Can/could
(1)表示能力
（2）表示允许
（3）表示推测
Can/be able to“设法做成某事”
表自身能力
表经过一段时间的努力后所具有的能力
=manage to do /succeed in doing
例1：---Could I borrow your dictionary
---Yes, of course you____.
A. might B. will
C. can D. should
析：选C。该句用can的委婉表达式could 来征求对方意见，could 和might通用，但回答时必须要用can或may，因此该题不选A.
归纳总结
May/might
(1)表示许可；
（2）祈使句表祝愿
（3）把握不太大的推测（肯定句）can(疑问句和否定句)
归纳总结
Will/would
1 表示意志意愿
2表示请求建议
3表示习惯性动作
注意：
Would/used to
归纳总结
May/might
(1)表示许可；
（2）祈使句表祝愿
（3）把握不太大的推测（肯定句）can(疑问句和否定句)
shall和should的用法
Shall
(1)用于一﹑三人称，征求意见或提议。
Shall we go out for lunch
(2)用于第二、三人称，表一种强烈的感情，如“命令，禁止，威胁，允诺”等.
If you dare do that, you shall be punished.
— The room is so dirty. _____ we clean it
— Of course. (2003北京春) A. Will B. Shall C. Would D. Do “The interest ______be divided into five parts, according to the agreement made by both sides. A. may B. should C. must D. shall
上述两题均考查 shall的含义，当shall 用于一、三人称疑问句中时，表示征求对方意见；用于二、三人称陈述句中，表示说话人给对方的命令、警告、允诺或威胁等。
should
should
should用于构成将来时是助动词。should用于表示“应当”“猜测”是情态动词。
(1) 表示义务，责任，意为“应当” 。
You should pay for your taxes.
（2） 表示推测，可能性。意为“可能，应该”。
It’s mid-night, he should be home.
（3） 表示惊讶和难以置信,表示说话人的感情(惊奇、愤怒、失望等)“竟然” 。
Why should he do such a thing
(4)shoud+have+done表示本应该做但实际上没做
2. 表示否定的情态动词的用法:
部分情态动词的否定式是情态动词中的考点
之一。
mustn’t 不准, 禁止
needn’t 没必要 ( = don’t have to )
can’t 不能; 不可能
may not 不可以; 可能不
shouldn’t 不应该 ( = ought not to )
Must/can`t
1 must 表示“必须 ”“应该”
2 must 表示“命令”“禁止”
3 must 表示猜测 否定式 can`t/couldn`t
must+be
Must+be doing
Must+have done 过去一定做了某事
can`t have done 不可能已经
Mustn`t 不许，不应该
例1：---Must I start at once
---No, you____.
A. needn’t B. mustn’t
C. can’t D. won’t
析：A。由语境可知该答句表示“不必”，而mustn’t表示“不准、禁止”，不符合语境，显然应使用needn’t表示“不必”，但肯定句回答继续用must。
反馈练习：workbook(p9)
1 Discuss the exercises in group of four.
2 Give you reasons why you choose it.
Homework
1 Recite the modal verbs and their usuage
2 Do exercises p9-10 in workbook.
可兼做行为动词的情态动词：need 、 dare
情态动词 (+动词原形)
行为动词
.
need
dare
2.尤其用于：
*否定句及疑问句中;
3.常以needn’t 和daren’t
的形式出现;
4.dare有其过去时dared.
多用于肯定句;
(sb.) need to do
dare to do
(sth.) need to be
done
(sth.) need doing
判断正误:
How dare you say such a thing
How dare you to say such a thing
He daren’t to speak English before such a
crowd, did he
He daren’t speak English before such a
crowd, dare he
Nobody need to be afraid of catching the disease.
Nobody need be afraid of catching the disease.
need 的被动含义：need，want, require, worth (adj.)后面接doing 也可表示被动
need doing =need to be done
表示推测的用法
can, could, may, might, must 皆可表示推测
情态动词+动词原形
表示对现在或将来的情况推测
不同的“肯定”程度可按下列层次排列：
He is at home. (事实)
He must be at home.（非常肯定的推断）
He could be at home.（很可能）
He ought to be at home.（很可能）
He may be at home.（仅仅可能而已）
He might be at home.（或许, 非常不确定）
He might not be at home.（也许不在家）
He may not be at home. （比might可能）
He couldn’t be at home.（很可能不在家）
He can’t be at home.（一定不在家）
He isn't at home.（事实）
二、情态动词+have done
表示对过去情况的推测
（一）should /ought to have done本来应做而未做，表达遗憾感彩
例1：I told Sally how to get there,
but perhaps I ____for her.(NMET94)
had to write it out
must have written it out
C. should have written it out
D. ought to write it out
析：选C。分析语境可知，口头上告知Sally如何去那里是不够的，所以我本应书面告知，却有没书面告知之，显得应使用should /ought to have written表示遗憾之情。
（二）may/might have done可能已做 / must have done 一定已做/can’t have done不可能做
例1：---Where is my pen
--- I _____it.(NMET88)
A. might lose
B. wouldn’t have lost
C. should have lost
D. must have lost
D
（三）could have done指本来能做而实际未做，表达遗憾的感彩
You could at least have sent five cards.你本来可以至少寄去5张明信片的。（说明没有寄那么多）
He must be reading, ____ he
You must do it yourself, ____ you
He must have gone over the article, ______he
It must have rained last night, _____ it
表猜测语气的反意疑问句的构成
isn’t
don’t
hasn’t
didn’t
