高考英语一轮复习 精细化学通语法 第九讲 情态动词与虚拟语气讲义.doc

第九讲 情态动词与虚拟语气情态动词(一)情态动词的基本用法1can/could(1)表示能力，意为“能，会”。the smallest good habits can make a big difference.最小的好习惯会产生很大的作用。it was several minutes before i could take in what he was saying.过了好几分钟，我才理解他说的是什么。(2)表示推测，意为“可能”，用于否定或疑问句中。can比could语气强。this cant/couldnt be done by him.这事不可能是他干的。(3)表示请求或允许。在疑问句中可以用could代替can，语气更委婉。could i use your phone, please?我可以用一下你的电话吗？(4)表示理论上的可能性。always believe that good things are possible, and remember that mistakes can be lessons that lead to discoveries.要始终相信美好事物的降临并非不可能，失误也会变成经验教训，从而获得更多发现。(5)用于否定句和疑问句，表示惊异、怀疑、不相信等态度。he cant/couldnt do this.他不可能这样干。(表示不相信)can this be done by him?这可能是他干的吗？(表示疑惑、惊讶)(6)用于固定结构中cant . too/enough表示“无论也不过分；越越好”。you cant be too careful while driving.你开车时越小心越好。cant help doing sth.表示“禁不住做某事”。hearing this story, i couldnt help laughing.听到这个故事，我禁不住大笑起来。名师指津can 和be able to都可以表示能力，二者有时可互换。但be able to可以表示“终于做成某事”，有更多时态和人称的变化；还可与某些情态动词或系动词连用，如might, ought to, seem等；还可用非谓语动词形式。if you have a good sleep, you will be able to work out this problem.如果你睡个好觉，那么你就能做出这道题。he seemed to be able to put complicated thought in simple words.他似乎能把复杂的思想用简单的话语说出来。she grasped my hand, not being able to say anything.她抓着我的手，什么话也说不出来。2may/might(1)表示请求和许可。在疑问句中，might可以代替may，语气更加委婉。may i ask if you are fond of traveling by sea?我可以问一下你是否喜欢乘船旅行？might i borrow your computer?我可以借一下你的电脑吗？(2)表示可能性，可以对现在、过去或将来进行推测。通常用于肯定句和否定句。might比may语气弱。parents may scold their children when they are untidy but they should also understand that their room is their own private space.当孩子不整洁的时候，父母也许会责骂孩子。但他们也应该理解孩子们的房间是他们的私人空间。if you forgot to turn it off when you went away, you might burn down the house.当你离开时如果忘记关掉它，你可能会把整个房子都烧毁的。(3)表示祝愿，常用结构为“may主语动词原形！”may you succeed!祝你成功！(4)用于固定结构中：“may/might as well动词原形”意为“最好，倒不如”。since it is raining hard, you may as well stay here.既然雨下得这么大，你倒不如待在这儿。3must(1)表示义务，意为“必须(主观意志)”。回答must构成的一般疑问句时，若是否定回答，一般不用mustnt，而用neednt或是dont have to，因为mustnt意为“绝不能，一定不要”，而没有“不必”的意思。men and women must be treated equally in education and employment.在教育和就业方面，男性和女性必须被平等对待。(2)表示猜测、推测，意为“想必，一定”。must常用于肯定句中，表示猜测。must do对现在或未来的事进行猜测must be doing对正在进行的事进行猜测must have done对已经发生的事进行猜测he thought that joe must be dead, but he didnt want to leave immediately.他以为乔一定死了，但是他不想立刻就离开。hurry up! they must be waiting for us now.快点！现在他们一定正在等我们呢。(3)用于否定句中，表示禁止。smoking must not be allowed in the office.严禁在办公室吸烟。(4)表示“偏要，非要不可”。must you make so loud noise?你非得弄出这么大声吗？名师指津must表示出于主观意识而必须做某事；have to表示由于某种客观原因而不得不做某事。除此以外，have to自身有人称和时态的变化。id also like to know how much i have to pay for the course.我还想了解一下学这门课程得付多少钱。it was then that i started to appreciate the tough choices she had to make on balancing family and work.就是在那时，我开始欣赏她不得不在平衡家庭和工作方面所作出的艰难选择。4shall(1)用于第一、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。shall the driver wait outside?司机在外面等着可以吗？(2)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、威胁等。i promised he shall get a present for his birthday.我许诺给他一件生日礼物。(3)用于条约、规定、法令、法律等，意为“必须”。it has been announced that candidates shall remain in their seats until all the papers have been collected.已经声明过，在所有试卷收上来之前，考生必须待在座位上。5should/ought to(1)表示责任、义务、劝告、建议等，意为“应该”。 表示责任或义务时，ought to等同于should，只是前者的语气稍重。why shouldnt we buy the lady a flower? it will make her feel better.为什么我们不应该给那位女士买一朵花呢？这会让她感觉好一些。you ought not to be so selfish.你不应该这么自私。(2)should表示出乎预料的口气，意为“竟然；居然”。that he should speak to you like that is quite astonishing.他竟然那样对你说话，真是令人惊讶。(3)should和ought to表示推测，指预期的可能性，意为“应该，估计”。he ought to/should be here on time he started early enough.他应该按时到这里的他很早就出发了。6will/would(1)表示自愿或主动提出做什么，如意志、愿望或决定等。will指现在，would指过去。can someone fetch some water?i will.有人能去取点水来吗？我去。(2)与will连用表示请求或要求，would比will更客气、委婉。而在句末用wont you表达邀请的语气。would you mind opening the window for me?你介意帮我打开窗户吗？(3)will表示规律性的“注定会”。wearing proper clothes is important too, for locals will judge you by what you wear.穿合适的衣服也很重要，因为当地人会根据你的穿着来评判你。7need/dareneed和dare既可用作情态动词，也可用作实义动词。用作情态动词时，主要用于否定句和疑问句中；用作实义动词时，可用于各种时态。(1)用作情态动词are you coming with me?i cant, alice. i darent.你要和我一起去吗？不行，艾丽丝。我不敢。its quite warm here; we neednt turn the heating on yet.这里很温暖。我们还不必开暖气。(2)用作实义动词you dont need to do it yourself.你不必亲自做这件事。most people hate harry but they dont dare to say so.大多数人对哈利敢怒不敢言。(二)情态动词have done1对过去发生的事情或状态进行推测must have done“(过去)一定做过”；语气比较肯定；用于肯定句may (might) have done“(过去)可能做过”；语气不确定；用于肯定句和否定句can (could) have done用于否定句和疑问句，表示怀疑或不确定looking at the large empty apartment, i became aware of how lonely my mother must have been in brazil herself.看着她又大又空的公寓，我开始理解妈妈独自一人在巴西一定很孤单。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。you cant have seen him just now. he has been abroad for nearly a month.你刚才不可能看见他了，他已经出国近一个月了。2表示“与过去事实相反”could have done过去本可以做某事但实际上没做neednt have done过去本不必做某事但实际上做了ought to/should have done过去本应该做某事但实际上没做oughtnt to/shouldnt have done过去本不应该做某事但实际上做了might have done过去可能做某事但实际上没做he could have gone on regretting it, as too many of us do.他本可以继续为此而遗憾，正如我们中很多人一样。you neednt have worked that late last night. it was harmful to your health.你昨天晚上本不必工作那么晚，那对你的健康有害。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 then.你本可以给他更多帮助，虽然你当时很忙。对点练1用情态动词或所给词的适当形式填空although you can find bargains in london, its not generally a cheap place to shop.life is unpredictable; even the poorest may/might become the richest.harry is feeling uncomfortable. he must_have_drunk (drink) too much at the party last night.why didnt you come to simons party last night?i wanted to, but my mom simply would not let me out so late at night.the school rules state that no child shall be allowed out of the school during the day unless accompanied by an adult.虚拟语气(一)虚拟语气用于条件状语从句中1虚拟语气在if条件句中的运用情况从句谓语动词主句谓语动词与现在事实相反过去式(be用were)should/would/could/might动词原形与过去事实相反had过去分词should/would/could/might have过去分词与将来事实相反过去式(be用were)should/would/could/might动词原形should动词原形were to动词原形if my brother were here, everything would be all right.要是我哥哥在这儿的话，一切都没问题了。if it should rain this afternoon, the basketball match would be put off.要是今天下午下雨，篮球比赛就会被推迟。if you had taken my advice, you would not have failed in the exams.如果你早听了我的建议，你考试就能通过了。2虚拟条件句中的省略与倒装如果虚拟条件句中含有were/had/should，有时可把if省略，把were/had/should提到主语之前形成倒装；若为否定形式，not不可提前。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。3错综时间条件句有时条件句的动作与主句动作发生的时间不一致，这时动词的形式应根据它们各自表示的时间加以调整。if we had booked a table earlier, we wouldnt be standing here in a queue now.如果我们早些订位子，现在也就不用站在这里排队了。(if条件句是对过去的虚拟，而主句是对现在的虚拟。)4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 wouldnt 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 taken part in the sports meeting, but i was ill that day.我本来可以参加运动会，但是那天我病了。(二)虚拟语气用于名词性从句中1在“it isimportant/necessary/natural/strange/essential/vital/. that .”句型中，从句谓语动词用“(should)动词原形”。its vital that we (should) take our safety driving along the road seriously.在路上开车时认真对待我们的安全非常重要。2在would rather (that)后的宾语从句中，从句的谓语动词如果表示现在或将来要发生的动作，从句用一般过去时；如果表示过去发生的动作，从句用过去完成时。id 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句中含有以下单词或其变形时，其后所跟的名词性从句(宾语从句、表语从句、主语从句或同位语从句)部分常用虚拟语气，其谓语动词形式为“should动词原形”，其中should可以省略。he suggested that we (should) start off early the next day.他建议我们第二天早点出发。名师指津当suggest表示“暗示，表明”之意，insist表示“坚持说”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 money.那个人坚持说他从没有偷过钱。4wish后宾语从句中的虚拟语气情况从句谓语动词与现在事实相反过去式(be动词一般用were)与过去事实相反had过去分词与将来事实相反would/could动词原形i wish (that) i were a bird and could fly freely in the sky.我希望我是一只鸟，能在天空中自由飞翔。i wish (that) i had met that film star yesterday.我多希望昨天见到了那个影星。5as if/though引导的表语从句和方式状语从句中的虚拟语气as if/though引导的从句中的谓语动词形式及使