1、2014 届牛津高三英语二轮复习语法专题专题 7 情态动词与虚拟语气一语法概念巧掌握：（一） 情态动词的用法 情态动词表示说话人对某一动作或状态的态度，可以表示“可能”、 “可以”、 “需要”、 “必须”或“应当”等之意。情态动词没有人称和数的变化。但不能单独作谓语动词用，必须和不带 to的不定式连用构成谓语动词。只有情态动词 ought 要和带 to 的动词不定式连用，在句中作谓语用。将情态动词置于主语之前即构成其疑问式，在情态动词之后加 not 既构成其否定式。现将各情态动词的基本用法分述如下： 1、can 和 could (could 为 can 的过去式) 的基本用法(1)表示能力，如
2、：He can speak English better than you. (2)在疑问句和否定句中表示“怀疑”、 “猜测” 或“可能性”，如：Can this green bike be Liu Dongs?(3)表示“许可”时 can 可以和 may 换用，如：You can (may) go home now. (4)如果要表示语气婉转，可用 could 代替 can，这时 could 不再是 can 的过去式，如：Could you come again tomorrow? (5)can 和 be able to 都可表示能力，两者在意思上没有什么区别。但是 can 只能有现在式和过
3、去式，而 be able to 则有更多的形式，如：He will be able to do the work better.2、may 和 might (might 为 may 的过去式) 的基本用法(1)表示允许或征询对方许可，有“可以”之意，如：You may use my dictionary. 在回答对方说“可以做某事”或“ 不可以做某事 ”时，一般多不用 may 或 may not，以避免语气生硬或不容气。而用比较婉转的说法进行回答。如：- May I use this dictionary? - Yes, please. 或 - Certainly. 在请求对方许可时，如果 M
4、ight I? 就比用 May I? 语气更婉转些，如：May I have a look at your new computer? 但是表示“ 阻止”或“禁止 ”对方做某事时，要用 must not 代替 may not，如： - May we swim in this lake? - No, you mustnt. Its too dangerous.(2)may 或 might 都可以表示可能性，表示“或许” 、 “可能” 之意，如果用 might 表示可能性，则语气更加不肯定，如：They may (might) be in the library now .3、must 的基本用法
5、(1)must 表示“必须 ”、 “应该”之意，其否定式 must not，缩写形式为 mustnt，表示“不应该” ，“不准”、 “不许可 ”或“禁止” 之意，如： We must study hard and make progress every day. You mustnt touch the fire. (2)对以 must 提出的疑问句，如作否定回答时，要用 neednt 或用 dont (doesnt) have to (不 必)来回答，而不用 mustnt，因为 mustnt 表示的是“禁止”或“不许可” 之意，如：- Must we finish the work tomo
6、rrow? - No, you neednt (dont have to), but you must finish it in three days. (3)在肯定句中 must 可以表示推测，表示“一定” 或“必定”之意，如：- Whose new bike can it be? - It must be Liu Dongs. I know his father has just bought him a new one.4、can, could, may, must 后接完成式的用法(1)can, could 后接完成式的用法：在否定句或疑问句中表示对过去发生过的事情的“怀疑”或“不肯定
7、”的态度，Could he have said so? 在肯定句中，可以表示过去可能做到而实际并没做到的事情，有“劝告” 或“责备”的语气。如：- When did you answer her letter? - Only yesterday. - Its too late. You could have answered it earlier, I am sure.(2)may, might 后接完成式的用法 表示对过去某事的推测，认为某一件事情在过去可能发生了。如果使用 might，语气就比较婉转或更加不肯定，如：Mary might have learned some Chinese
8、before. 可以表示过去本来可以做到而实 际没有做到的事情，有 “劝告”或“责备”的语气，如：You didnt do the work well that day. You might have done it better. (3)must 后接完成式的用法：表示对过去某事的推测，认为某事在过去一定做到 了，如：Liu Dong isnt in the classroom. He must have gone to the library. 5、have to 的基本用法have to 和 must 的意义相近，只是 must 侧重表示说话人的主观看法，而 have to 则表示客观需
9、要，如：I must study hard. I had to give it up because of illness. 6、ought to 的基本用法(l)表示根据某种义务或必要“应当” 做某事，语气比 should 强，例如：Everyone ought to obey the traffic regulations. (2)表示推测，注意与 must 表示推测时的区别：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) ，T
10、his is where the oil ought to be. (比较含蓄) ；(3)“ought + have+ 过去分词 ”表示过去应做某事而 实际未做。例如：You ought to have helped him. (but you didnt) 这时，ought 与 should 可以互相换用。注意，在美国英语中 ought to 用于否定和疑问句时 to 可以省略。例如： Ought you smoke so much? You oughtnt smoke so much.7、dare 的基本用法(l)dare (dared 为其过去式) 作情态动词用时，主要用于否定句，疑问句
11、和条件从句中，如：Dared he bread the traffic regulations again? (2)在现代英语中 dare 常用作行为动词，其变化与一般行为动词相同，如：She dares to stay at home alone at night.8、need 的基本用法(1)need 作情态动词用时，主要用于否定句和疑问句中，如：He neednt worry about us now. (2)need 也可作为行为动词用，可用于肯定句，否定句和疑问句中，其后可接名词、代词、动名词或带 to 的动词不定式为其宾语。如： You need to practise readi
12、ng aloud every day. (3)neednt 后接完成式可以表示过去做了一件本来不必要做的事情，如：- Did you answer the letter yesterday? - Yes, I did. - But you neednt have answered it.9、shall 的基本用法(1)shall 用作情态动词时，用于第二、三人称，表示说活人的意愿，可表示“命令”、 “警告”、 “强制”、 “威胁”或 “允诺”等意，如：He shall go first, whether he wants to or not. (2)在疑问句中，shall 用于第一、三人称，表
13、示说话人的征询对方意见或请求指示，如：Shall I open the door?10、should 的基本用法(1)should 作为情态动词可以表示 “建议”或“劝告” ，有“应该”之意，如：You should learn from each other. (2)should 后接完成式表示过去没有做到本来应该做的事情，或是做了本来不应该做的事情。如：You should have give him more help. 11、will 的基本用法(1)用于各人称，可以表示“意志”或“决心” ，如：I have told him again and again to stop smoki
14、ng, but he will not listen. (2)在疑问句中用于第二人称，表示说话人向对方提出请求或询问对方的意愿，如：Will you please tell me how to get to the Capital Gymnasium? (3)will 可以表示一种习惯性的动作，有“总是”或“ 会要”之意，如：Every morning he will have a walk along this river.12、would 的基本用法(1)would 作为 will 的过去式，可用于各人称，表示过去时间的“意志”或“决心”，如：He promised he would ne
15、ver smoke again.(2)在疑问句中，用于第二人称，表示说话人向对方提出请求或许问对方的意愿时，比用 will的气更加婉转，如：Would you like some more coffee? (3)在日常生活中，学用“I would like to”表示“我想要 ”或“我愿意”之意，以使语气婉转，如：I would like to do Ex.2 first.(4)would 可以表示过去的习惯动作，比 used to 正式，并没有“现已无此习惯”的含义。如：Last year our English teacher would sometimes tell us stories
16、 in English after class. / During the vacation he would visit me every week. (5)表料想或猜想，如：It would be about ten when he left home./ What would she be doing there?/ I thought he would have told you about it.13、used to, had better, would rather 的用法(1)used to 表示过去的习惯动作或状态，现在已不存在，在间接引语中，其形式可不变，例如：He told
17、 us he used to play foot ball when he was young. 在疑问句、否定句、否定疑问句或强调句中，可有两种形式。疑问句：Did you use to/ Used you to go to the same school as your brother? 否定句：I usednt to / didnt use to go there. (usednt 也可写作 usent)；否定疑问句：Usent you to/ Didnt you use to be interested in the theatre? 强调句：I certainly used to/
18、did use to smoke, but it was a long time ago.；其反意疑问句或简略回答中，也有两种形式：She used to be very fat. didnt she?/ use(d)nt she? Did you use to play chess? Yes, I did./ Used you to get up early in the morning? Yes, I did./ used to.(2)had better 意为“最好”，后接不带 to 的不定式，例如：- We had better go now . - Yes, we had (wed
19、better/ we had better)./ Hadnt we better stop now? (Had we better not stop now?)/ I think Id better be going. (用于进行时态，表“最好立即”)/ You had better have done that (用于完成时态，表未完成动作) 注：had better 用于同辈或小辈，对长辈不可用。(3)would rather 意为“ 宁愿”，表选择，后接不带 to 的不定式，例如：Id rather not say anything./ Would you rather work on
20、a farm?/ - Wouldnt you rather stay here? - No, I would not. Id rather go there. 由于 would rather 表选择，因 而后可接 than，例如：I would rather work on a farm than in a factory. / I would rather watch TV than go to see the film/ I would rather lose a dozen cherry trees than that you should tell me one lie./ Id ra
21、ther you didnt talk about this to anyone. (句中的 d rather 不是情态动词，would 在此是表愿望的实义动词)。（二）虚拟语气的用法1、语气的种类：英语句子中谓语动词的语气有四种：（1.） 直陈语气（The Indicative Mood）直陈语气用于直截了当地陈述事实、描述状态：He has published quite a number of essays this year .他今年已发表了好几篇论文。（2.） 祈使语气（The Imperative Mood）祈使语气用于提出请求、命令、建议或是劝告等：Wait outside un
22、til you are asked . 请在外面等候，请你进再进去。Lets just take a break, shall we ? 我们休息一会儿，好吗？（3.） 疑问语气( the interrogative mood ) ：用来提出问题Where are from ?（4.） 虚拟语气（The Subjunctive Mood）虚拟语气用于表示主观愿望和假设的虚拟情况。虚拟语气不太顾及事实的存在，它表现出说话人的主观因素比较多。所以说话人所讲的内容往往是与事实相反的；或是其实现的可能性微乎其微，甚至于没有实现的可能性。当然，有时为了使说话的语气客气、缓和、委婉，也使用虚拟语气。I w
23、ish you were more careful .但愿你更细心一些。If I had more money, I would buy a bigger apartment.我要是有再多一点钱，我就买一套更大一些房子。Would you mind shutting the door ? 劳驾您把门关上。2、虚拟语气的种类：虚拟语气用来表示说话人的主观愿望或假想，所说的是一个条件，不一定是事实，或与事实相反。虚拟语气在条件句中应用比较多；条件句可分为两类，一类为真实条件句，一类为非真实条件句。非真实条件句表示的是假设的或实际可能性不大的情况，故采用虚拟语气。3、真实性条件句（1.）真实条件句用
24、于陈述语气，假设的情况有可能发生,各种结构如下：条件从句 主句一般现在时 shall/will + 动词原形祈使句 情态动词一般现在时If he comes, he will bring his violin. 如果他来，会带小提琴来的。【典型例题】The volleyball match will be put off if it_.A. will rain B. rains C. rained D. is rained【解析】B 真实条件句主句为将来时，从句用一般现在时。【点拨】1. 在真实条件句中，主句不能用 be going to 表示将来，该用 shall, will.（错） If
25、you leave now, you are never going to regret it.（对） If you leave now, you will never regret it.（2.） 表示真理时，主句谓语动词不用 shall （will） +动词原形，而直接用一般现在时的动词形式4、非真实条件句（1.） 虚拟语气可以表示过去，现在和将来的情况，时态的基本特点是时态往后推移（2.） 虚拟语气表时间 从句 主句 例句与现在事实相反的假设一般过去时（ be 用were）Would / should / could / might / ought to + 动词原形1. If they
26、 were here, they would help you.2. If we had enough money , we would buy a computer .3. If I were you , I wouldnt do it .4. If it rained tomorrow , wed stay at home .5. It would be odd if she were awarded the first prize .与过去事实相反的假设过去完成时 Should / would / could / might + have+ 过去分词1. If he had come y
27、esterday, I should have told him about it.2.If I had been in her position Id have quit .3. If the weather hadnt been so bad , we might have gone out .4. If he had apologized , you should have done so too.5. I should never have done it if I hadnt been so hard up .与将来不大可能发生的事情的假想一般过去时 / should/would+
28、动词原形Should / would / could / might / ought to + 动词原形1. If you succeeded, everything would be all right.2. If they invited me , I would certainly attend it .3. If he went , would you go too ?与将来事实相反的假设were+ 不定式Should / would / could / might / ought to + 动词原形1. If she were to lose her place they would
29、 be ruined .2.If you were to speak to him , it would carry more weight .5、混合条件句(也叫：错综时间条件句 )有时，主句与从句的动作发生在不同的时间，主句从句谓语动词的虚拟语气形式因时间不同而不同，这种条件句叫做混合条件句If you had asked him yesterday, you would know what to do now. 如果你昨天问过他，今天就知道做什么了。 （从句与过去事实相反，主句与现在事实相反。 ）1. If it had rained last night（过去）, it would b
30、e very cold today （现在）.如果昨晚下过雨，今天就会很冷了。2. If youd listened to me , you wouldnt be in such trouble now . 如果你听了我的话，你现在也不会这样麻烦了3. If it hadnt been for her care , I should not be speaking to you now. 如果不是她照顾我，我也不会在这里和你讲话4. If the doctor had come in time , any would still be alive . 如果医生及时赶到，AMY现在还活着。6、含
31、蓄条件句：含蓄条件句是指非真实条件句中的条件从句有时不表出来,只暗含在上下文中。含蓄条件句常见的表达方式有:（1.） 定语从句和状语从句Anyone who had married such a girl as she would have been regretful . 谁娶了像她这样的姑娘都会后悔的help was promised where it should become necessary . 要是需要的话就答应给予帮助（2.） 介词及介词短语but that, as though, once , but for, without , with , under , underco
32、ndition , supposing , suppose , as if , on condition that , in the past 等But for his pension , he would starve .要不是有养老金，他都要饿死了Without your help , I couldnt have achieved all this . 要不是有你帮助我不会取得这些成就With his aid , you would succeed . 如果有了他的帮助，你就会成功。Plants would die without water on the earth . 地球上如果没有
33、水，植物就会死的But for the fog we would have reached our destination long ago . 要是没有雾的话，我们很早就到目的地了Under more favourable conditions we could have finished the task . 如果条件对我们更有利，我们就会把工作完成得更好（3.） 连词 otherwise, or, butHe would have given you more help , but he has been so busy . 他本来要多给你一些帮助，只是他太忙了Seize the cha
34、nce , otherwise you would regret it . 如果不抓住这个机会，你会后悔的He felt very tired yesterday , or he would have helped you . 他昨天觉得很累，不然会帮你的（ 4.） 通过分词短语表示条件Given more time, we could have done it better.Legalizing this drug would have disastrous consequence . 使毒品合法化会有灾难性的后果（ 5.） 用动词不定式表示条件It would be a mistake n
35、ot to help him.She would have done anything to make amends . 她会做任何事来弥补特殊情况：情态动词在日常用语中用得很多，使句子显得比较委婉；这类谓语算不算虚拟语气很难说，但有两点是肯定的：一是它们不受时态的影响，虽然形式接近过去式，却常指现在的情况，而且和虚拟语气在形式上一致，在不少情况下几乎可以说是一种含蓄的虚拟条件句；二是它们不表示事实，常带有主观色彩，因而使句子显得很委婉。I should think that might be a good solution .could I trouble you with a questi
36、on ?could you lend me some money ?would you mind taking part ?would you like some tea ?7、虚拟语气在宾语从句中的运用（1.） 虚拟语气用在 would rather，would（just ）as soon，would sooner，would prefer（希望）等后接的宾语从句中。意指某人宁愿让另一个人做某事，其后的宾语从句的谓语动词需用虚拟语气。若表示现在或将来要做某事，从句谓语动词需用一般过去时，表示过去已经做的事，从句谓语动词用过去完成时。The manager would rather his d
37、aughter did not work in the same office经理宁愿她女儿不与他在同一间办公室工作。To be frank，Id rather you were not involved in the case坦率地说，我希望你不要卷入这件事。You dont have to be in such a hurryI would rather you went on business first你没有必要这么着急，我宁愿你先去上班。Id rather you didnt make any comment on the issue for the time being我倒希望你暂
38、时先不要就此事发表意见。Frankly speaking ，Id rather you didnt do anything about it for the time being坦白地说我宁愿你现在对此事什么也不做。Wouldnt you rather your child went to bed early？为什么你不愿让你的孩子早点上床呢？【点拨】若某人愿自己做某事， would rather 后用动词原形 I would rather stay at home today would rather than 中用动词原形 I would rather stay at home than
39、go out today（ 2.） 在表示命令、建议、要求等一类动词后面的从句中，像 order, suggest, propose, require, demand, request, insist, command, insist + （should） doI suggest that we （should） hold a meeting next week. 我建议下周召开个会议。He insisted that he （should ） be sent there.他要求被派到那儿去。【点拨】如 suggest, insist 不表示 “建议“ 或“坚持要某人做某事时 “，即它们用于其
40、本意“暗示、表明“、“坚持认为“时，宾语从句用陈述语气。判断改错： （错） You pale face suggests that you（should）be ill.（对） Your pale face suggests that you are ill.（错） I insisted that you（ should）be wrong.（对） I insisted that you were wrong.（3.） wish 的用法1）wish 后面的从句，表示与事实相反的情况，或表示将来不太可能实现的愿望时，其宾语从句的动词形式为：主句 从句从句动作先于主句动词动作（be 的过去式为 wer
41、e） 现在时 过去时从句动作与主句动作同时发生（had+过去分词）过去时/现在时过去完成时将来不大可能实现的愿望 将来时/现在时 would/could +动词原形I wish I were as tall as you. 我希望和你一样高He wished he hadnt said that. 他希望他没讲过那样的话I wish it would rain tomorrow. 我希望明天下雨就好了I wish that he werent so lazy . 但愿他不那么懒He wishes that he were a teacher . 他希望他是个老师就好了I wish that h
42、e had not made so much fuss about it . 但愿那时他对这事不那么大惊小怪I wish that the rain would stop . 要是雨停就好了2）在“it is wished that”句型以及作名词所引起的表语和同位语从句中也要求使用虚拟语气，用法同上。3) wish to do；wish sb / sth to doI wish to see the manager. = I want to see the manager. 我希望见一见经理。I wish the manager to be informed at once. （= I wa
43、nt the manager to be informed at once.）我希望经理能马上得到消息8、 虚拟语气用在表语从句或同位语从句中当某些表示建议、请求、命令等主观意向的名词作主语时，其后的表语从句或同位语从句需用虚拟语气，其表达形式为 should 动词原形或直接用动词原形。这类名词常见的有：advice， suggestion，proposal，order， demand，desire，request，requirement，recommendation , aim , wish , necessity , preference , motion , plan，idea，reso
44、lution 等。We are all for your proposal that the discussion be put off我们都赞成你提出的将讨论延期的建议。The suggestion that the mayor present the prizes was accepted by everyone由市长颁发奖金的建议被每个人接受。Any proposals that john should be dismissed must be resisted . 必须抵制任何开除 JOHN的提议His idea that we should take up the matter wi
45、th a special board is fairly resonable . 他建议我们以一个专门委员会处理这件事，这的确有道理Our suggestion is that we should put on a play at the english evening . 我们建议在英语晚会上演一个剧9、 在主语从句中的应用It is / was + necessary + that + 主语 + should + 加动词原形，should 可省略，表示建议、命令、请求、道歉、怀疑、惊奇等可用的词有：suggested, ordered, required, proposed, demand
46、ed , requested, insisted , important, necessary, natural, imperative, strange , a pity, a shame, no wonder , essential , advisable , mandatory , obligatory , vital , compulsory , crucial , fitting , better , best , appropriate , recommended 10、虚拟语气在其他状语从句中的使用（1.） 虚拟语气用在目的状语从句中在由 lest , for fear that
47、 , in order that , so that , in case of 等引导的目的状语从句中需用虚拟语气，表示“以防，以免”等意思，其谓语动词多由 should / could / might + 动词原形构成，should 也可省略。He was punished lest he should make the same mistake again他被处以惩罚以免他再犯。I reminded her twice of it lest she should forget . 我提醒她两次，怕她忘记I will not make a noise for fear that I shou
48、ld disturb him . 我不会出声的，以免打扰他I have come all the way here in order that you should understand me . 我到这里来为的是你能理解我He put his coat over his son in case he should catch cold . 他把大衣盖在儿子身上以免他着凉注意：如果 in order that 和 so that 前的主句是现在时，其后的从句有时也可用 can , may + 动词原形。Ask him to hurry up with the letters so that I
49、 can sign them . 让他带着信赶快来以便我签字在以 lest 和 in case 引导的目的状语从句中谓语动词若属于过去时，一般要用虚拟语气， should + 动词原形，若谓语动词不是过去时，也可以用成述语气。take warm clothes in case the weather is cold . 带上厚衣服以防天变冷。（2.） 虚拟语气在方式状语从句中在 as if（as though）引导的方式状语从句中，常用虚拟语气，表示 似乎，好象的意思，其动词形式与 wish 后接宾语从句中的形式相同。Alan talked about Rome as if he were a Roman艾伦谈起罗马来好像他是个罗马人一样。I feel as if I were ten years younger . 我觉得我仿佛年轻了 10 岁He tal
