英语情态动词的用法应注意哪些事项,

英语情态动词的用法应注意哪些事项,
英语情态动词的用法应注意哪些事项,

英语情态动词的用法应注意哪些事项,
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 1．“I don’t think Mike can type.”
“Yes, he can.”
2．I can speak fluent English now , but I couldn’t last year.
在肯定句中,表示客观可能性,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)

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. 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.
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?
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.
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.)
(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.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.
(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、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. 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.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. 1． Might I borrow your pen?
2． I wonder if I might speak to your son.
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.

may用于祈使句表示祝愿 1． May you succeed.
2． Long may he live! 愿他能持续住下去.
3． May you have many more days as happy as this one.
4． 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”,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.
二．must和have to
情态动词 用法 例句
must 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 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.
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)
表示有把握的推测,意为“一定、准是、相必”,只用于肯定句中 1． It must be my mother.
2． You must be hungry after a walk.
3． There must be a hole in the wall.
have to
have to “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. 1． The film is not interesting. I really must go now.
2． I have to go now, because my mother is in hospital.
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. 1．I had to work hard when I was your age.
2．I will have to learn how to use a computer.
3．In order to take the exam, we’ll have to finish the whole book by the end of this month .
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、二、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?
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)
should 表示劝告或建议,意为“应该” 1． What should I do?
2． Should I trust him?
3． You should read his new book.
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.
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)
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?
五．will和would
情态动词 用法 例句
will/would 用于表示意志或意愿.will指现在,would指过去. 1． He is the man who will go his own way. (他首歌自行其是的人.)
2． They said they would meet us at 10:30 at the station.
表示请求、建议等,用would比用will委婉、客气. 1． Will you please take a message for him?
2． Would you please tell me your telephone number?
表示习惯或倾向,意为“总是,惯于”.will至现在,would指过去. 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.
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.
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.
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,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）, 1．—Need we leave soon?
—Yes, you must.(No, you needn't)
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.
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 ）,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 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)
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 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.
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?
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.
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)
说明：should与ought to 表示“应该”时的区别
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.如：
You should help them with their work.
You are his father. You ought to get him to receive good education.
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” 1． She must have gone through a lot.
2． He must have visited the White House during his stay in the United States.
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） 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,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. 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.
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.
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.
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．I would rather have taken his advice.
2．I would rather not have told him the truth.

我就我想的起来的说几个：疑问句Must I ……？回答时，NO,you need not.
should have done sth.意思说（本应该做某事而没做）
should not have done sth.(本不应该做某事却做了）
need have done sth.(过去本来有必要去做某事但没有做)
need not have done sth .(过...

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我就我想的起来的说几个：疑问句Must I ……？回答时，NO,you need not.
should have done sth.意思说（本应该做某事而没做）
should not have done sth.(本不应该做某事却做了）
need have done sth.(过去本来有必要去做某事但没有做)
need not have done sth .(过去本来没有必要做某事但却做了)
情态动词按照其可能性大小强度排是：must >can >may>might >ought to

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一、用“情态动词＋have ＋done”结构表示对过去动作的推测，试题中常用过去时态或过去的时间状语给以暗示。情态动词的这一用法可以用 “对立统一”来概括。
1．当试题的前句和后句在动作和意义上相互补充说明，且整个句意在动作和时间上是一个整体时，我们可用“统一”关系来解决这样的试题。常见的结构有：
must have done： 表示对过去动作的肯定推测，常译作“一定做了……”...

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一、用“情态动词＋have ＋done”结构表示对过去动作的推测，试题中常用过去时态或过去的时间状语给以暗示。情态动词的这一用法可以用 “对立统一”来概括。
1．当试题的前句和后句在动作和意义上相互补充说明，且整个句意在动作和时间上是一个整体时，我们可用“统一”关系来解决这样的试题。常见的结构有：
must have done： 表示对过去动作的肯定推测，常译作“一定做了……”，只能用于肯定句中。其否定形式为can‘t／couldn‘t have done 疑问式为Can／Could...have done？。
could ／might have done：表示对过去发生的动作的可能性推测，常译作“可能做了……”。如：
1) Sorry I‘m late． I ＿＿＿＿＿ have turned off the alarm clock and gone back to sleep again．
A． might B． should C． can D． will
该题前句说明了结果，后句接着说出了产生这种结果的可能性，对前句进行补充说明。分析选项可知本题应选A。
2) My sister met him at the Grand Theater yesterday afternoon， so he ＿＿＿＿ your lecture．
A．couldn‘t have attended
B．needn‘t have attended
C．mustn‘t have attended
D．shouldn‘t have attended
该题前句叙说一个客观事实，后句对前句进行补充说明，分析选项可知C是错误的; 而B、D两项不符合题意。故本题选A。又如：
Jack ＿＿＿＿ yet， otherwise he would have telephoned me．
A．mustn‘t have arrived
B．shouldn‘t have arrived
C．can‘t have arrived
D．need not have arrived （C）
2．当试题的前后句在动作和意义上构成转折关系时，常借助“but， however， instead”等词来表示过去的动作与客观事实不符，这时我们就可以用“对立”关系来解决这样的试题。这种结构常见的有：
should have done ／ ought to have done：表示过去本应该做某事而实际上没有做。
should not have done ／ ought not to have done：表示过去本不应该做某事但事实上却做了。
need have done：表示过去本来有必要去做某事，但事实上没有做。
need not have done：表示过去本来没有必要做某事，但事实上却做了。如：
3) I was really anxious about you． You ＿＿＿＿＿ home without a word．
A．mustn‘t leave B．shouldn‘t have left
C．couldn‘t have left D．needn‘t leave
分析该题前后句之间的关系和语气可知，事实上是 “本不应该离家出走却走了”，故本题选B。
4) I told Sally how to get here， but perhaps I ＿＿＿＿＿ for her．
A．had to write it out
B．must have written it out
C．should have written it out
D．ought to write it out
由句中的连词but可知前后句之间是对立关系，分析题意可知本题应选C。
二、考查情态动词基本用法之间的比较和辨析。最近几年试题中常借助具体的语境来考查考生对那些最常见的情态动词的基本用法的理解和把握，因此在做这样的试题时应认真分析语境中所含的实际意义，并结合情态动词的基本含义和用法做出正确的选择。
5) —Is John coming by train？
—He should， but he ＿＿＿＿＿＿ not． He likes driving his car．
A．must B．can C．need D．may
mustn‘t 表示“禁止、不准”；cannot 表示“不可能”；need not 表示“不必要”；may not 表示“可能不”。分析语境可知本题应选D。
6) —I hear you‘ve got a set of valuable Australian coins．＿＿＿ I have a look？
—Yes， certainly．
A．Do B．May C． Shall D．Should
分析语境可知这是在征求对方的许可，may表示“答应、可以”，语气比较委婉 shall常用于第一、三人称作主语的疑问句中，表示征求对方意见和指示，假如此空用shall，则意为“要（我）看一下吗？”，不符合上下文意思。故本题选B。
7) Mr Bush is on time for everything． How ＿＿＿＿ it be that he was late for the opening ceremony？
A．can B．should C．may D．must
must be 表示肯定的猜测，只能用于肯定句中，由题意可知本题应选A。
8) —Are you coming to Jeff‘s party？
—I‘m not sure． I ＿＿＿＿ go to the concert instead．
A．must B．would C．should D．might
由题意和下句中的 “I‘m not sure” 可知这段对话中存在一种可能性推测，might可以用来表示一种比较委婉的可能性判定，故本题选D。又如：
I should have been there， but I ＿＿＿＿＿ not find the time．
A．would B．could C．might D．should
分析题意可知第二个分句表示过去的某种能力；C 项只表示语气上的可能性，与题意不符。故本题选B。
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; shouldn‘t
mustn‘t 表示“不可以；禁止”，分析题意可知第二个空表示某种可能性，故本题选B。
10) —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
分析题意可知因为“我弟弟要来看我”，所以“不能留下”，因此对别人的邀请或要求应给予礼貌的拒绝。A 项表示“禁止”；C项表示“不必要”；而D项表示“不会”，均不符合题意。故本题选B。又如：
—Could I borrow your dictionary？
—Yes， of course you ＿＿＿＿＿．
A．might B．will C．can D．should
11)—When can I come for the photos？ I need them tomorrow afternoon．
—They ＿＿＿＿＿ be ready by 1200．
A．can B．should C．might D．need
该题考查情态动词should的基本含义，分析句意可知本题应选B。又如：
The old man is always hunting the lions， so terrible things ＿＿＿＿ happen to him．（上海‘96）
A．might B．would C．should D． could 烠
12)The fire spread through the hotel very quickly but everyone ＿＿＿＿ get out．
A．had to B．would C．could D．was able to
该题考查了could和be able to的区别，二者都可表示过去时间的能力，但假如表示过去成功地做了某事只能使用was ／ were able to do，故本题选D。
13)—Shall I tell John about it？
—No， you ＿＿＿．I‘ve told him already．
A．needn‘t B．wouldn‘t C．mustn‘t D．shouldn‘t
情态动词shall在试题中表示征询对方意见或请求指示。答句暗示 “没有必要了”，故本题选
A

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