2020版一轮复习英语外研·全国版学案：语法第二部分第三讲情态动词和虚拟语气

第三讲情态动词和虚拟语气



情态动词的基本用法　

[全析考法]
单句语法填空/单句改错
1．(2018·北京高考)In today's information age, the loss of data ________ cause serious problems for a company.
解析：can　句意：在如今的信息化时代，丢失数据可能会给一个公司造成严重的问题。can在此表示客观可能性，意为“可能会，有时候会”。
2．(2016·全国卷Ⅲ)Truly elegant chopsticks might ________ (make) of gold and silver with Chinese characters.
解析： be made　根据语境可知，筷子是被制造的。此处为含有情态动词的被动语态might be done。
3．(2015·四川高考改编)You ________ be careful with the camera.It costs!
解析：must　句意：你必须要小心使用这个相机。它很贵重！ 根据后面的“It costs！”可知，此处是说话人对使用相机的人提出的要求，must意为“必须”，表示说话人主观上的要求，语气强烈。
4．(2018·全国卷Ⅱ)As a kid, I loved to watch cartoons, but no matter how many times I asked to watch them, my parents would not to let me.________________
解析：去掉let前的to　情态动词would表示“意愿”时后面直接接动词原形。
5．(2016·全国卷Ⅱ)We can chose between staying at home and taking a trip.________________
解析：chose→choose　情态动词can后面接动词原形。chose是choose的过去式形式。
[谨记规则]
(一)can, could
用　法
例　句
表示能力，意为“能，会”；could表示过去的能力。
She can speak French fluently.
她能讲一口流利的法语。
can可用于肯定句中，表示客观或理论上的可能性。
An experienced teacher can make mistakes.
一位有经验的老师也会犯错。
表示请求或允许。在疑问句中，could可以代替can，语气更委婉，肯定回答时要用can，不用could。
—Can/Could I use your bike tomorrow morning？
—Yes, you can.
——明天上午我可以用你的自行车吗？
——是的，可以。
表示说话者的主观推测，意为“可能”，用于否定句和疑问句中。can比could语气强。
He can't be our manager. He has gone to Beijing.
他不可能是我们经理。他已经去北京了。
表示惊异、怀疑、迷惑等态度，常用于否定句和疑问句中。
How can you treat me like that？
你怎么能那样对我？
用于固定习语中：can't ... too/enough (无论……也不过分；越……越好)；can't but do sth. (不得不，只好)；can't help doing sth. (禁不住做某事)。
I can't thank you too much for all your help to my son while we were away from home.
我非常感谢你，在我们不在家时帮助我的儿子。
One cannot but admire her determination.
人们不得不佩服她的决心。

(二)may, might
用　法
例　句
表示请求或许可。在疑问句中，might可以代替may，语气更加委婉。给予许可时用may，不用might。
—Might I ask for a picture of your little daughter？
—Yes, you may.
——我可以要一张你小女儿的照片吗？
——是的，可以。
表示推测，意为“或许，可能”，通常用于肯定句和否定句中。might比may语气弱。
—I really don't like James.
Why did you invite him？
—Don't worry. He might not come.
——我真的不喜欢詹姆斯。
你为什么邀请他？
——别担心。他或许不会来。
表示祝愿，常用结构为：May＋主语＋动词原形！
May you be happy every day！
愿你快乐每一天！
用于固定短语中：may/might as well＋动词原形(不妨，还是……为好)；may/might well＋动词原形(很可能……)。
You may/might as well tell him the truth.你不妨告诉他事实吧。
He may/might well stay in Beijing now.
他现在很可能待在北京。

(三)must, have to
用　法
例　句
表示义务，意为“必须”。must强调说话人的主观看法，have to则强调客观需要；在回答带有must的问句时，否定式常用need not (needn't)或don't have to，而不是用must not。
We must act as quickly as possible now. Just tell us whether you can undertake the task or not.现在我们必须尽快采取行动。你仅仅告诉我们你能否承担这项任务就行。
I have to go now, because my mother is in hospital.我现在不得不走了，因为我母亲在住院。
must用来表示推测，意为“一定”，只能用在肯定句中。must的肯定程度比can强。
You must be hungry after a long walk.
长途跋涉之后，你一定饿了。
must表示“偏要，非要……不可”。常用于疑问句和条件句中，偶尔也用于陈述句中。
If you must go, at least wait until the storm is over.
如果你非要走，至少要等到暴风雨停了。
mustn't表示禁止，意为“不得，不允许；一定不要”。
You mustn't play with the knife, or you may hurt yourself.你千万不要玩刀，否则会伤到自己的。

(四)shall
用　法
例　句
用于第一、三人称的疑问句中，表示说话者征求对方的意见。
Shall he come in now？
要不要让他现在进来？
用于第二、三人称的陈述句中，表示说话者的命令、警告、威胁、允诺、决心等。
You shall be punished for what you have done.你必须为你的所作所为受到惩罚。
用于条约、规定、法令、法律等文件中表示义务规定，意为“必须”。
One of our rules is that every student shall wear school uniform while at school.
我们有一条规定，那就是每名学生在校期间都必须穿校服。

(五)should, ought to
用　法
例　句
should表示责任、义务、劝告、建议等，意为“应该”。
We should be strict with ourselves.我们应该严格要求自己。
should表示出乎意料、惊讶的口气，意为“竟然，居然”。
Such a gentleman should do that.这样一位绅士竟然会做那种事。
ought to表示义务、责任、劝告等，意为“应该”，语气比should略重。
You ought not to be so selfish.
你不应该这么自私。
should和ought to表示推测，指合乎理想的情况或结果，意为“按说应该”。
Try phoning Robert — he should be home by now.
给罗伯特打个电话试试，他现在应该到家了。

(六)will, would
用　法
例　句
与各种人称连用，用于陈述句中，表示主语的意志、意愿或决心。will指现在，would指过去。
I will never talk to him again.
我再也不会和他说话了。
表示征求意见或提出请求，多用于第二人称疑问句中。would比will语气委婉。
Will/Would you please close the window？
请把窗户关上好吗？
表示习惯性动作、固有属性或必然趋势，意为“总是；习惯于”。will指现在，would指过去。
Fish will die without water.
没有水，鱼会死的。

(七)need, dare
用法
例句
need既可作情态动词，也可作实义动词；作情态动词时，表示“需要”，常用于否定句、疑问句和条件句中。needn't表示“不必”；对need引出的一般疑问句作肯定回答时用must而不用need，作否定回答时用needn't。
I needn't use a clock to wake me up, because at six o'clock each morning the train comes by my house.
我不必用闹钟来叫醒自己，因为每天早上六点都有火车从我家旁边经过。
dare既可作情态动词，也可作实义动词；作情态动词时，表示“敢，敢于”，后跟动词原形，常用于疑问句、否定句和条件句中。
I am so afraid that I dare not move.
我吓得一动也不敢动。


情态动词＋have done　

[全析考法]
单句语法填空/单句改错
1．(2018·天津高考改编)I can't find my purse. I could ________ (leave) it in the supermarket yesterday, but I'm not sure.
解析：have left　句意：我找不到我的钱包了。我昨天可能把它落在超市里了，但我不确定。根据句中的时间状语yesterday可知空格处是对过去发生事情的推测，需用“情态动词＋have done”。
2．(2013·全国卷Ⅱ改编)Since nobody gave him any help, he ________ have done the research on his own.
解析：must　句意：既然没有人帮助他，他一定是独自完成了这项研究。根据题干中“Since nobody gave him any help”可判断设空处表示肯定的推测。
3．(2013·浙江高考改编)I ________ (enjoy) myself more — it was a perfect day.
解析：couldn't/can't have enjoyed　句意：我玩得再开心不过了——这是完美的一天。“can't/couldn't ... more”表示最高级的意思；根据题干中的was可知设空处表示“对过去发生的事情的态度”，故答案为couldn't/can't have enjoyed。
4．(2015·天津高考改编)I needn't worried before I came to the new school, for my classmates here are very friendly to me.________________
解析：worried前加have　needn't have done表示“本没有必要做”。

[谨记规则]
1．对过去发生的事情或状态进行推测
must have done sth.
“(过去)一定做了某事”；语气比较肯定；用于肯定句
may (might) have done sth.
“(过去)可能/也许做了某事”；语气不确定；用于肯定句和否定句
can (could) have done sth.
“本来能够/可以做某事”；用于否定句和疑问句，表示对过去发生的行为的怀疑或不确定
It must have rained last night, for the road is quite muddy.
昨晚一定下雨了，因为路很泥泞。
The boy might have known the truth, but I am not quite sure.那个男孩也许知道了真相，但我不是很确定。
I didn't see her in the meeting room this morning. She couldn't have spoken at the meeting.
我今天上午没在会议室看见她，她不可能在会议上讲话。
2．表示“与过去事实相反”
could have done sth.
过去本可以做某事但实际上没做
needn't have done sth.
过去本不必做某事但实际上做了
ought to/should have done sth.
过去本应该做某事但实际上没做
oughtn't to/shouldn't have done sth.
过去本不应该做某事但实际上做了
might have done sth.
过去可能做某事但实际上没做

You could have done better, but you didn't try your best.
你本可以做得更好，但是你没有尽力而为。
I needn't have taken the umbrella, for the weather is fine.
天气这么好，我本没必要带雨伞的。
You ought to have done this exercise more carefully.
你本应该更仔细地做这个练习。
You might have given him more help, though you were busy.你本可以给他更多帮助，虽然你当时很忙。


虚拟语气　

[全析考法]
单句语法填空/单句改错
1．(2018·北京高考改编)They might have found a better hotel if they ________ (drive) a few more kilometers.
解析：had driven　句意：如果他们开车再多走几千米的话，他们或许就会找到一家更好的旅馆。主从句皆为对过去的虚拟，从句中应使用过去完成时表示对过去的虚拟。
2．(2018·天津高考改编)If we ________ (catch) the flight yesterday, we would be enjoying our holiday on the beach now.
解析：had caught　句意：如果昨天我们赶上了航班的话，我们现在正在海滩上享受我们的假期了。此句是错综时间虚拟语气，由yesterday可知从句是对过去的虚拟(用过去完成时)，主句是对现在的虚拟。
3．(2018·江苏高考改编)It's strange that he ________have taken the books without the owner's permission.
解析：should　句意：真奇怪，他居然没有得到主人的允许就把那些书拿走了。在it is strange that ...; it is important that ...; it is necessary that ...等句式中，that 引导的从句要用“should＋动词原形”作谓语。
4．(2018·江苏高考改编)There is a good social life in the village, and I wish I ______ (have) a second chance to become more involved.
解析：had　句意：在这个村子里有很好的社交生活，并且我希望我能再有一次机会更多地参与其中。动词wish后面的宾语从句要用虚拟语气。若表示与现在相反的虚拟，从句用一般过去时； 若表示与过去相反的虚拟，从句用过去完成时或would/could have done。根据句意可知，此处表示与现在的情况相反，故用动词的过去式。
5．(2016·全国卷Ⅱ)Some classmates suggest we can go to places of interest nearby.________________
解析：can→should或去掉can　suggest在此处表示“建议”，后面接宾语从句时，从句中谓语用“should＋动词原形”，should可以省略。
6．(2015·四川高考)If you are me, would you talk to them？________________
解析：are→were　根据语境可知，此处是虚拟语气，表示对现在的虚拟，动词用过去式，所以要把are改为were。
[谨记规则]
(一)虚拟条件句的基本用法
1．if虚拟条件句
(1)基本构成
时间
if从句谓语动词形式
主句谓语动词形式
对现在的虚拟
过去式(be的过去式用were)
should/would/could/might＋动词原形
对过去的虚拟
had＋过去分词
should/would/could/might＋have＋过去分词
对将来的虚拟
should＋动词原形
should/would/could/might＋动词原形
过去式(be的过去式用were)
were to＋动词原形

(2)错综时间虚拟条件句
当从句、主句所表示的行为发生的时间不一致时，动词的形式要根据它所在的时间作出相应的调整。
If you hadn't left home without a word, your parents wouldn't be so worried now.
要不是你一言不语地离开家，你父母现在就不会那么担心了。(从句与过去事实相反，主句与现在事实相反)
(3)省略if的倒装句
if虚拟条件状语从句中出现were, had, should时，可省略if，把were, had, should提到句首，变为倒装句式。
Had he caught the morning train, he would not have been late for the meeting.
要是他赶上了早晨的火车，那他就不会开会迟到了。
2．含蓄条件句
(1)有时假设的情况不用条件句表达，而是用but for, without等介词(短语)或上下文来表示。
We wouldn't have finished the project on time without your timely help.如果没有你的及时帮助，我们就不能按时完成那项工程了。
(2)用连词otherwise, or等暗示后文与前面的情况相反，从而引出后文的虚拟语气。
I was ill that day. Otherwise, I would have taken part in the sports meeting.我那天病了，否则，我就参加运动会了。
(3)虚拟条件通过but暗示出来，模式为“虚拟情况＋but＋真实情况”。
I would have delivered a speech, but I had a cold that day.
我本来可以演讲的，但是那天我感冒了。
(二)虚拟语气在名词性从句中的用法
1．主语从句中的虚拟语气
(1)某些It is/was＋形容词/过去分词/名词＋that引导的主语从句中，主语从句要用虚拟语气，即“should＋动词原形”，should可省略。
It's vital that we (should) take our safety driving along the road seriously.重要的是我们应该认真对待我们的安全驾驶。
(2)用于本句型常见的形容词、过去分词、名词
形容词
necessary, important, best, right, impossible, preferable, desirable, advisable, essential, urgent, strange等。
过去分词
通常表示提议、要求、命令等，如suggested, required, requested, demanded, urged, decided, proposed, ordered, desired, advised等。
名词
pity, regret, desire, rule, shame, honour, surprise等。

2．宾语从句中的虚拟语气
(1)宾语从句在表示“提议”“要求”“命令”“意志”等动词后，其谓语动词用“(should)＋动词原形”表示虚拟。常见的此类动词有insist (坚持要求，坚决主张), order, command, advice, suggest (建议), propose, recommend, ask, demand, require, request, urge, arrange, desire, intend, direct等。
He suggested that we (should) start off early the next day.
他建议我们第二天早点出发。
[易错提醒]　当suggest表示“暗示，表明”之意，insist表示“坚持说，坚持认为”之意时，suggest/insist后的宾语从句不使用虚拟语气，而使用陈述语气。
The smile on his face suggested that he was satisfied with our work.他脸上的微笑表明他对我们的工作很满意。
The man insisted that he had never stolen the money.
那个人坚持说他从没有偷过那笔钱。
(2)wish后接that引导的宾语从句用虚拟语气，其谓语动词的形式为：
时间
从句谓语动词形式
对现在的虚拟
过去式(be的过去式用were)
对过去的虚拟
had＋过去分词
对将来的虚拟
would/could/might＋动词原形
I wish (that) I were ten years younger.
但愿我能年轻十岁。
I wish (that) I had met that film star yesterday.
我多希望昨天见到了那个电影明星。
(3)would rather后接宾语从句用虚拟语气，其谓语动词的形式为：
时间
从句谓语动词形式
对现在的虚拟
过去式(be的过去式用were)
对将来的虚拟
对过去的虚拟
had＋过去分词

I'd rather he had gone to the seaside with me the day before yesterday.要是他前天和我去海边就好了。
3．表语从句中的虚拟语气
(1)句子主语是表示“愿望”“劝告”“建议”“主张”“命令”“决定”等行为动词派生出来的同根名词时，其表语从句常用虚拟语气“(should)＋动词原形”结构。这类名词有suggestion, proposal, request, advice, decision, requirement等。
Our only request is that this (should) be settled as soon as possible.我们唯一的要求是这事应该尽可能快地解决。
(2)虚拟语气可用于as if, as though引导的表语从句和方式状语从句：
时间
从句谓语动词形式
对现在的虚拟
过去式(be的过去式用were)
对过去的虚拟
had＋过去分词
对将来的虚拟
would/could/might＋动词原形
She looks as if nothing had happened to her.
她看起来好像什么事都没有发生似的。
He opened his mouth as if he would say something.
他张开嘴好像要说什么。
[特别注意]　如果从句中描述的事情可能会发生，那么从句中的谓语动词可用陈述语气。
It sounds as if it is raining.听起来像是在下雨。
4．同位语从句中的虚拟语气
当表示建议、提议、命令、要求等的名词作主语或宾语时，其同位语从句中的谓语动词用“should＋动词原形”，should可以省略。常见的这类名词有：
advice建议　 decision决定　　 demand要求
desire渴望 idea想法 motion提议
order命令 plan计划 proposal提议
request要求 suggestion建议
We agreed to the order that the task (should) be completed at 5 o'clock.我们都同意这个命令：五点完成这项任务。
5．2个特定句式中的虚拟语气
(1)if only引导的条件句及感叹句
对过去的虚拟
对现在的虚拟
对将来的虚拟
had＋过去分词
过去式(be的过去式用were)
would/could/should/might＋动词原形

(2)It is (high/about/very) time (that)...
从句中谓语动词用过去式或“should＋动词原形”。
If only I had seen the film.要是我看过那部电影就好了。
It is high time that we should start/started out.
我们该出发了。

语法填空解题“2注意”
1．若句中谓语动词为原形，在其前设纯空格题时，注意考虑情态动词。然后根据句意或句式结构填入恰当的情态动词。
2．一旦判断所给动词在句中作谓语，就要考虑其时态、语态、语气、主谓一致等，特别是注意虚拟语气中的时态。判断虚拟语气，除了常见的if虚拟条件句，还应注意其他常搭配虚拟语气的标志词， 如suggest, would rather, as if, wish, otherwise, or, but for等。
据第1条解题
1．You can never be too careful while driving. You know, many traffic accidents result from carelessness.
2．You've made lots of mistakes in the exam, many of which could have been avoided had you been more careful.
3．As the new manager is kind and patient, there should be no trouble in his getting on well with the workers.
4．Smoking is not allowed here, sir. Go to the smoking room over there, if you must.
5．—Who is playing the piano?
—It must be Kate. No one else in our school can play it so beautifully.
据第2条解题
6．It is required by law that a driving test (should)be_taken (take) before a man gets a license.
7．He telephoned to inform me of your birthday, or I would_have_known (know) nothing about it.
8．The national smog serves as a constant reminder, indicating that it's high time we reflected (reflect) on ourselves.
9．—It would_be (be) cool if I won this contest. I don't think I'm good enough, though.
—Give it a shot. You never know.
10．The Antarctica is so mystically described by some people. If only I had_been (be) there before.
短文改错解题“2视角”
1．看句中情态动词是否运用正确；
2．看是否考查虚拟语气。若是考查虚拟语气，注意分清主句与从句中的时态关系以及不同句式中的虚拟语气构成形式。
据第1条解题
1．Life is unpredictable; even the poorest may to become the richest.去掉to
2．I love the weekend, because I needn't to get up early on Saturdays and Sundays.去掉to
3．We needn't bought so much food now that Suzie won't be with us for dinner.bought前加have
据第2条解题
4．One day, a friend of mine, Tom, contacted me and suggested that we started to swim.started→start
5．In the past two years, you have helped us a lot, without which we couldn't have been made such great progress in English.去掉been
6．However, it's high time that immediate measures must be taken.must→should

Ⅰ.语法填空
Harvard is older than the United States. In the early 1630s some settlers suggested that a university __1__ (found) just to improve the quality of their descendants so that they could __2__ (well) build the new home. Thus, it was established in 1636 by vote of the Great and General Court of the Massachusetts Bay Colony.
Like many other __3__ (university) at that time, the Harvard at the early stage often ran into financial crisis. The school board often had to go to Europe to raise __4__ (donate), but as you can predict, they often came back __5__ their hands empty.
In 1638, John Harvard, pastor of Charlestown, passed away. He left his library and half his estate to the institution, __6__ were the biggest donation ever since its establishment. Therefore, the university was named after his name. Today, you can find a statue of John Harvard __7__ (stand) in front of the University Hall in Harvard Yard, and it is perhaps the University's best __8__ (know) landmark.
Like other world famous universities, Harvard too has many colleges and Harvard Business School is one of them. There is __9__ saying in education that Harvard is the crown of American education __10__ Harvard Business School is the shining diamond on it.
语篇解读：本文是一篇说明文。文章介绍了哈佛大学创建初期遇到的困难、名称的来历以及其地位。
1．(should) be founded　考查动词的语态和虚拟语气。主语a university和动词found之间是被动关系，故用被动语态；suggest表示“建议”时，后接宾语从句，从句用虚拟语气，谓语动词用“(should＋)动词原形”。
2．better　考查副词的比较级。17世纪30年代早期，一些殖民者建议建立一所大学以提高他们后代的素质，以便于他们能更好地建造新的家园。根据语境可知，空处表示“更好地”，故用副词比较级。
3．universities　考查名词复数。和当时的其他许多大学一样，早期的哈佛大学经常遭遇金融危机。university为可数名词，该处表示“其他许多大学”，故用复数形式。
4．donation(s)　考查词性转换。学校董事会不得不经常去欧洲筹集捐款，但正如你所能预测的，他们经常空手而归。根据该句中的及物动词raise可知，空处作该及物动词的宾语，故用名词形式。
5．with　考查介词。with表示“具有，带有”。
6．which　考查定语从句。分析句子结构可知，空格处引导非限制性定语从句，修饰先行词his library and half his estate，并在从句中作主语，故用which引导该定语从句。
7．standing　考查非谓语动词。今天，你可以在哈佛广场的大学礼堂前发现一尊站立着的John Harvard的雕像，这也许是这所大学最著名的地标。a statue of John Harvard和动词stand之间为逻辑上的主谓关系，故用现在分词作宾语补足语。
8．known　考查词性转换。根据空处后的名词“landmark”可知，空处修饰该名词，表示“知名的，著名的”，故填形容词known。
9．a　考查冠词。该处泛指“一句格言”，且saying的读音以辅音音素开头，故用不定冠词a。
10．and　考查连词。在教育界有一句名言：哈佛是美国教育的王冠，哈佛商学院是王冠上闪亮的钻石。空格前后为并列关系，故用连词and。
Ⅱ.短文改错
It's a pleasure for me give a short speech here today. Recently I've found that some of classmates study too lately into the night. Nor do they spare enough time for a rest during the day. No wonder they often can't fall asleep in class. Also, some classmates seldom have a breakfast. Certainly, which will surely do harm to their healthy. In my opinion, having enough sleep and a proper diet are extremely important. We must learn to make wisely use of our time. Only in this way can we keep fit or study well. Do you agree with me? Thanks to listening.
答案：第一句：give前加to
第二句：lately→late
第四句：can't→can
第五句：去掉a
第六句：which→it; healthy→health
第七句：are→is
第八句：wisely→wise
第九句：or→and
第十一句：to→for