2019版英语高三一轮复习系列江苏专用文档：第二部分语法核心突破第六课时 学案

第六课时　情态动词和虚拟语气[感 悟 高 考]1.________ not for the support of the teachers, the student could not overcome her difficulty.(2017·江苏卷)A.It were   B.Were itC.It was   D.Was it答案　B　[虚拟语气中，be动词统一用were；虚拟语气的省略形式是把if省略，同时把were/should/had提前，即Were/Should/Had I...，故选B。句意：要不是老师们的支持，该生是无法克服困难的。]2.Samuel, the tallest boy in our class, ________ easily reach the books on the top shelf.(2017·北京卷)A.must   B.should  C.can   D.need答案　C　[must必须；should应该；can能；need需要。句意：Samuel，我班最高的男生，能很轻松地够着书架顶上的书。]3.If the new safety system ________ to use, the accident would never have happened. (2017·北京卷)A.had been put   B.were putC.should be put   D.would be put答案　A　[句意：如果这个新的安全系统被投入使用的话，这个事故就不会发生了。根据主句would never have happened确定是对过去情况的虚拟，所以从句谓语用had done形式。]4.My room is a mess, but I ________ clean it before I go out tonight. I can do it in the morning.(2017·天津卷)A.daren’t   B.shouldn’tC.needn’t   D.mustn’t答案　C　[句意：我的房间很乱，但是在今晚我出去之前不需要打扫，我可以明天早晨再打扫。daren’t不敢；shouldn’t不应该；needn’t不需要；mustn’t不许。根据句意，故选C。]5.—Do you have Betty’s phone number?—Yes. Otherwise, I ________ able to reach her yesterday.(2017·天津卷)A.hadn’t been   B.wouldn’t have beenC.weren’t   D.wouldn’t be答案　B　[句意：——你有贝蒂的电话号码吗？——有。否则我昨天就联系不到她了。标志词otherwise相当于一个条件状语从句：If I hadn’t have her phone number，即对过去的虚拟的条件状语从句，可以判断出主句用wouldn’t have done表示对过去情况的虚拟，故选B。][要 点 精 析]一、情态动词的基本用法1.can 和could的用法 (1)表示“能力，能够”。—No one can be compared with Yao Ming in playing basketball.—Oh, you are really his big fan.——在打篮球方面，无人能与姚明相媲美。——你真是姚明的铁杆粉丝。(2)表示“许可”，此时can可以和may换用。You can (may) go home now.你现在可以回家了。(3)表示惊讶，常用在否定句和疑问句中。How could you do such a silly thing?你怎么能做那样的蠢事呢？(4)cannot...too/enough表示“无论……也不过分”；“越……越好”。I can’t thank you too much for all your help to my son while we were away from home.我们不在家时，你对我儿子的帮助，我怎样感谢你都不过分。2.may和might的用法(1)may和might表示“许可”。—May I take the book out?—I’m afraid not.——我能将书带出去吗？——恐怕不行。(2)“may/might as well＋动词原形”意为“最好；不妨”。If you think the price of beef is too high, you may as well buy some pork. It depends on you.如果你认为牛肉太贵的话，你不妨买些猪肉。你自己决定。3.must的用法(1)表示必要性，意为“必须”。—Shall I inform him of the change of the schedule right now?—I am afraid you must, in case he comes late for the meeting.——我现在通知他日程表的变动吗？——恐怕你必须通知他，以免他开会迟到。(2)表示禁止(用于否定句)。The new law states that people mustn’t drive after drinking alcohol.新颁布的法律禁止人们酒后驾车。(3)表示“偏偏，偏要”。If you must go, at least wait until the storm is over.如果你非要走的话，至少等到暴风雨结束。4.need的用法(1)need作情态动词时，主要用于否定句和疑问句中。He needn’t worry about us now.他现在不必为我们担心。(2)need也可作实义动词，用于肯定句、否定句和疑问句中，其后可接名词、代词、动名词或带to的动词不定式作宾语。You need to practise reading aloud every day.你有必要每天都大声朗读。5.shall和should的用法(1)shall的用法①用于第一、第三人称疑问句中，表示说话人征求对方的意见或向对方请示。—What time shall I pick you up at your house tomorrow, sir?—I haven’t decided on the time.But I will call you.——先生，我明天什么时候到你家接你呢？——我还没有决定时间，但是我会给你打电话的。②用于第二、第三人称陈述句中，表示说话人给对方的命令、警告、允诺或威胁。—Will you read me a story, Mummy?—OK. You shall have one if you go to bed as soon as possible.——妈妈，给我讲个故事好吗？——好的，如果你尽快上床睡觉我就给你讲一个。③用于第三人称作主语的陈述句中，在条约、规定、法令等文件中表示义务或规定。The National Party congress shall be held every five years.党代会每五年举行一次。(2)should的用法①表示义务、职责等，意为“应该”。The children should be taken good care of.这些孩子应该受到好的照顾。②表示说话人的惊奇、愤怒、失望等特殊情感。How should I know where you’ve left your bag?我怎么知道你把包丢在哪里了？6.will和would的用法(1)表示意志、意愿和决心，would用于过去的情况。—Goodbye, John. Come back again sometime.—Sure. I will.——再见，约翰。欢迎再来。——好的，我会的。—Why didn’t you come to Simon’s party last night?—I wanted to, but my mom simply would not let me out so late at night.——你昨晚为什么没有参加Simon的聚会？——我想去，但是妈妈不愿意让我自己在这么晚的时间出去。(2)will可以表示一种习惯性的动作，有“总是”或“总要”之意。Every morning he will have a walk along this river.每天早晨，他总是沿着小河散步。(3)would可以表示过去的习惯性动作，比used to正式，但没有“现已无此习惯”的含义。When we worked in the same firm several years ago, we would often go to the cinema together.当几年前我们在同一家公司工作时，我们常常一起去看电影。二、情态动词表推测的用法1.can表推测。(1)can表示推测时常用于否定句和疑问句，语气很强烈。Mr.Bush is on time for everything.How can it be that he was late for the meeting?布什先生做什么事情都很准时，他怎么可能开会迟到呢？(2)can用于肯定句中，常表示客观的可能性。It is usually warm in my hometown in March, but it can be rather cold sometimes.我的家乡在三月份通常很暖和，但有时候也会相当冷。2.may用于肯定句中可以用来表示推测，意为“可能”；用于否定句中也可以表示推测，may not意为“可能不”，表示一种不太确定的语气。The traffic is heavy these days. I might arrive a bit late, so could you save me a place?这些天交通很繁忙，我可能会来晚一点，请你帮我保留个位置好吗？Some people who don’t like to talk much are not necessarily shy; they may just be quiet people.言语不多的人未必就是害羞。他们或许就是安静的人。3.must 表示推测时只能用于肯定句中，意为“一定，必定”，表示十分肯定的语气(在疑问句或否定句中要用can)。—It’s the office！So you must know eating is not allowed here.—Oh, sorry.——这是办公室！所以你一定知道这里不许吃东西。——噢，对不起。4.should 用来表示推测时意为“应该”，即含有“按道理来说应当如此”的意思。There shouldn’t be any difficulty passing the road test since you have practised a lot in the driving school.既然你在驾校训练了那么多，通过路考应该没什么困难。三、“情态动词＋have done”的用法情态动词＋have done用法must have done一定做过某事，其否定形式为can’t/couldn’t have donecan/could have done(1)本来能够做但却未做(2)可能做过某事can’t/couldn’t have done不可能做过某事may/might have done或许/可能做过某事should/ought to have done本该做但却未做，其否定形式表示本不该做但却做了needn’t have done做了本没有必要做的事情It must have rained last night，for the road was quite wet.昨晚肯定下雨了，因为路面十分潮湿。You needn’t have taken a taxi here，for it was near my home.你本来不必打车来这里的，因为这里离我家很近。一、if条件句中的虚拟语气if条件从句从句的谓语形式主句的谓语形式表示现在情况动词过去式(be的过去式用were)should/would/could/might＋动词原形表示过去情况had＋过去分词should/would/could/might＋have＋过去分词表示将来情况should＋动词原形should/would/could/might＋动词原形动词过去式were to＋动词原形If I were you，I would take an umbrella.如果我是你，我会带把伞。If I saw/should see/were to see him tomorrow，I would invite him home.如果明天见到他，我会邀请他到我家。二、错综时间条件句和含蓄条件句中的虚拟语气1.当条件状语从句表示的行为和主句表示的行为所发生的时间不一致时，被称为“错综时间条件句”，动词的形式要根据它所表示的时间做出相应的调整。If we had booked a table earlier，we wouldn’t be standing here in a queue.如果我们早一点订一张桌子，现在就不会站在这里排队了。2. 有时假设的情况并不以条件从句表示，而是由otherwise，but，or，without，but for等来引导或者通过上下文引出。Without your help，I wouldn’t have succeeded anyway.＝If you hadn’t helped me，I wouldn’t have succeeded anyway.没有你的帮助，我无论如何也不会成功。三、if的省略如果if条件句中含有were，had或should时，可把if省略，把were，had或should提到主语之前形成倒装，若为否定形式，not不可提前。Were it sunny tomorrow，we would go to the Great Wall.如果明天是星期天，我们就能去长城。四、名词性从句中的虚拟语气1.用于表示建议、愿望、命令等动词后的宾语从句中常见的动词有：demand，order，require，insist，suggest，propose，advise，request，urge，command，prefer，desire，recommend等。宾语从句中的虚拟语气结构为“should＋动词原形”，should可以省略。They insisted that the boy (should) go with them.他们坚决要求那个小男孩跟他们一起去。2. 用于主语从句中在It is desired/suggested/proposed/recommended/necessary/important/strange/natural/a pity/essential＋that从句中，从句的谓语动词用“should＋动词原形”，should可以省略。It is suggested that the meeting (should) be put off till next week.人们建议会议推迟到下周。3. 用于表语从句和同位语从句中在suggestion，proposal，order，plan，idea，request，advice等名词后的表语从句和同位语从句中要用虚拟语气，其构成是“should＋动词原形”，should可以省略。My idea is that we (should) think it over before accepting it.我的意见是在接受之前我们要反复考虑。Your suggestion that the door (should) be shut when we leave is reasonable.你的那个当我们离开的时候应该关上门的建议是合理的。五、wish宾语从句中的虚拟语气1. 对现在情况的虚拟：wish＋主语＋动词过去式(be用were)I wish (that) I were a bird and could fly freely in the sky.但愿我是一只小鸟，能在天空自由飞翔。2. 对过去情况的虚拟：wish＋主语＋had＋过去分词I wish you had come to the lecture.但愿你当时来听报告了。3.对将来情况的虚拟：wish＋主语＋would/could/might＋动词原形We wish we would live on the moon one day.但愿我们有一天能住在月球上。六、其他句型中的虚拟语气1.would rather后的宾语从句中，表示愿望，意为“宁愿；但愿”。用一般过去时表示与现在或将来事实相反；用过去完成时表示与过去事实相反。When my father is upset，he would rather we left him alone.当我的父亲烦恼的时候，他更喜欢我们不打扰他。2. 在“It is (about/high) time＋that从句”中，谓语动词常用过去式或“should＋动词原形”表示虚拟语气，注意should不可省略。It’s high time that we devoted ourselves to environmental protection.是我们致力于环境保护的时候了。3.as if，as though引导的表语从句和方式状语从句中常用虚拟语气，与现在事实相反用一般过去时；与过去事实相反用过去完成时。It seems as though it were spring already.看起来好像已经是春天了一样。4.if only引导的感叹句中，用虚拟语气表示愿望。Look at the trouble we’re in.If only we had taken our teacher’s advice!看看我们所处的困境，要是我们接受老师的建议就好了！[解 题 策 略]1.句型提示法虚拟语气可以用在状语从句、名词性从句、定语从句中，在不同的从句中，虚拟语气用不同的动词形式来体现，如：if非真实条件句(分三种情形)，wish后的宾语从句，It is time that...的定语从句等。所以，掌握了各类从句中虚拟语气的动词形式，就基本上掌握了虚拟语气的用法。If we ________ the other road，we might have arrived here in time for the meeting.A.take   B.had takenC.took   D.have taken答案　B　[句意：如果我们走另一条路的话，我们或许能够及时到达这里参加这次会议了。根据主句的谓语动词might have arrived可以推出，本句是与过去事实相反的虚拟语气，所以if条件句中应该用过去完成时。]2.特定词汇暗示法英语中某些短语如：If it were not for/had not been for, but for..., if only..., without等，往往要采用虚拟语气，它们对于解答试题有很大的帮助，掌握了这些要点知识，做起题来也就很容易了。Thank you for all your hard work last week.I don’t think we ________ it without you.A.can manage   B.could have managedC.could manage   D.can have managed答案　B　[根据without you可知，本句是对过去事情的虚拟推测，故用could have＋过去分词。][针 对 训 练]1.Had the governments and scientists not worked together，AIDS-related deaths ________ since their highest in 2005.(2016·浙江卷)A.had not fallen   B.would not fallC.did not fall   D.would not have fallen答案　D　[句意：如果各国政府和科学家们不一起努力的话，与艾滋病相关的死亡就不会自 2005 年的最高水平降下来。根据Had the governments and scientists not worked together可知事情发生在过去，因此是对过去情况的虚拟，主句用would have done形式。故选D。]2.George ________ too far.His coffee is still warm.(2016·浙江卷)A.must have gone   B.might have goneC.can’t have gone   D.needn’t have gone答案　C　[句意：乔治不可能走远。他的咖啡还是热的。can’t have done表示对过去否定的推测，意为“不可能做了……”。]3.I love the weekend，because I ________ get up early on Saturdays and Sundays.(2016·北京卷)A.needn’t   B.mustn’tC.wouldn’t   D.shouldn’t答案　A　[句意：我喜欢周末，因为每逢周六、周日我不需要早起。A项意为“不需要”；B项意为“禁止”；C项意为“不会”；D项意为“不应该”。根据句意可知选A项。]4.Why didn’t you tell me about your trouble last week? If you ________ me，I could have helped.(2016·北京卷)A.told   B.had toldC.were to tell   D.would tell答案　B　[句意：你上周为什么不告诉我你的麻烦。如果你告诉了我，我能够帮助你。根据last week可知事情发生在过去，因此是对过去情况的虚拟。根据主句谓语动词could have done可知，从句应用过去完成时had done。故选B。]5.It was really annoying；I ________ get access to the data bank you had recommended.(2016·天津卷)A.wouldn’t   B.couldn’tC.shouldn’t   D.needn’t答案　B　[句意：这真的很让人恼火，我无法使用你推荐的那个数据库。根据句意可知应选couldn’t “不能够”。wouldn’t “不愿意”；shouldn’t “不应该”；needn’t “不必”。]6.—What’s your feeling now?—I am terribly sorry.If only I ________ here yesterday!A.came   B.would have comeC.have come   D.had come答案　D　[if only “要是……就好了”，从时间状语yesterday来看，这是对过去所发生事情的虚拟，所以用过去完成时。]7.It’s everybody’s desire that every effort ________to reduce the pollution in our hometown.A.was made   B.be madeC.will be made   D.would be made答案　B　[desire后的宾语从句及所在句子中的名词性从句，均应使用虚拟语气，虚拟形式为“should＋动词原形”，其中should可省略，故选B。]8.They must have enjoyed themselves there，otherwise they ________ so long.A.can’t have stayed   B.wouldn’t have stayedC.can’t stay   D.wouldn’t stay答案　B　[由must have enjoyed可知，otherwise后的情况是与过去的事实相反的，故谓语动词应用would have done。]9.________ more energy to my study instead of being crazy about Internet games，I would be sitting in a comfortable office now.A.If I devoted   B.Had I devotedC.Would I be devoted   D.Should I be devoted答案　B　[此句为错综时间条件句，从句用过去完成时，表示与过去的事实相反，如果省略if要用倒装句；主句根据now用“would＋动词原形”的形式，表示与现在的事实相反。]10.Grace doesn’t want to move to New York because she thinks if she ________ there, she wouldn’t be able to see her parents very often.A.lives   B.would liveC.having asked   D.were to live答案　D　[根据wouldn’t be able to...可知这是将来时的虚拟语气，从句可用三种形式lived，should live，were to live，所以选D。]11.Don’t handle the vase as if it ________ made of steel.A.is   B.wereC.has been   D.had been答案　B　[as if从句中，对现在的虚拟谓语动词用were。]12.Jack is a great talker.It’s high time that he ________ something instead of just talking. A.will do   B.has doneC.do   D.did答案　D　[在句型 It’s high/very time that...中， 从句中的谓语动词用did或should do，所以选D项。]13.________ another national referendum(公投) of Brexit be held，perhaps the UK would be kept in the EU and better promote a socially progressive Europe.A.Would   B.Could  C.Might   D.Should答案　D　[句意：如果再举行一次英国脱欧的全民公投，也许英国就会留在欧盟并且更好地推动欧洲的社会进步。分析句子成分可知，本题为if引导的非真实条件句。根据句意可知本题为对将来时间的虚拟语气，在if引导的非真实条件句中，如果从句省略if则从句需要部分倒装。故should符合题意。]14.It’s a sad fact of life：lies are lies，and sometimes the truth ________ lie as well.A.shall   B.should  C.can   D.must答案　C　[句意：这是一个可悲的生活事实：谎言就是谎言，而有时真相也可能撒谎。can意为“可能”；shall表征求对方意见，表命令、警告、威胁等；should意为“应该，竟然，万一”；must意为“必须；一定；偏要”。]