最新届高考英语语法精品学案专题八 情态动词和虚拟语气.docx

1、最新届高考英语语法精品学案专题八 情态动词和虚拟语气 情态动词主要用来表示说话人的情感、态度等，是中学英语语法的重点，也是高考的热点，是单项填空必考的一个知识点。情态动词在近五年高考中主要考查四点：情态动词表示推测和可能性的用法；情态动词与虚拟语气；情态动词表达“情感、态度、语气等”；情态动词表示 “必要性”等方面的用法。虚拟语气的考点主要集中在名词性从句、条件句中的用法，以及错综条件句中虚拟语气的应用。一、 情态动词表推测的用法 情态动词 意义 语气 句式 语境 例句 备注 must一定 可能性最大 肯定句 对具体事实的判断A：Look，someone is coming. Who can

2、it be? B: It may be our headmaster. A: It cant be him. He has gone to Shanghai. B: It must be Mr. Wang. He looks like our headmaster. That may not be true. He couldnt have discovered the truth. 对现在的行为或状态的推测：must/may/might/can/coulddo 对过去的行为或状态的推测：must/may/might/can/could have done may/might(might可能性

3、小于may)可能可能性较小，尤其might最不肯定肯定句、否定句(可能不)can/could (could可能性小于can)可能疑问句、否定句(不可能)、(could有时也用于肯定句)有时会肯定句情态动词 意义 语气 句式 语境 例句 备注 should /ought to应该 ，理应 理论上Its 8 oclock now. He should be in the office now. Hi, Mum! Im on the bus. I should be home in about ten minutes. 常表示在一段时间内可能发生的事或某人的期望。一般句末有时间状语，或有语境暗示。所

4、表示的猜测发生的可能性很大。 注意：should (ought to)表示推测是高考考查的重点和难点。如： When can I come for the photos？I need them tomorrow afternoon. They _ be ready by 12：00. Acan Bshould Cmight Dneed 【解析】 BA项表示推测时常用于否定句和疑问句中。C项表示推测语气不太肯定。should意为“按理说，理应”，既回答了顾客的询问，不失礼貌，又为照片有可能尚未洗好，顾客到时取不到留下了回旋的余地，体现了店主的精明与用词经过仔细推敲。 二、情态动词的其他用法1ca

5、n, could, may, might情态动词意义 例句 备注 can/could能力 I can see some birds flying in the sky. Could the girl read before she went to school? could表示泛指过去的某一能力。表示过去有能力并且成功地做了某事，通常用was/were able to do，相当于managed to do/succeeded in doing。如：Because he practised hard, he was able to pass the driving test. 情态动词意义 例

6、句 备注 can/could允许(有时可与may互换) Can/May I have a look at your photos？ can与could、may与might不表时态差异，只是语气上的差别，could/might比can/may更委婉。注意在回答时不能用could/ might。 请求 Can/Could you lend me a hand？Yes, I can. 情态动词意义 例句 备注 may/might允许或请求 You may take this if you like.May/Might I ask for a photo of your baby？ can与could

7、、may与might不表时态差异，只是语气上的差别，could/might比can/may更委婉。注意在回答时不能用could/ might。 2.must, should 情态动词意义 例句 备注 must 必须 We must help each other to overcome the difficulties. Must I finish the work today？No, you neednt/you dont have to./Yes, you must. You mustnt take photos here, and it is forbidden. must表示主观意志，

8、have to表示客观。如：They had to speed up, for the weather turned terrible. Must I/we？的否定回答不能用mustnt。 偏要硬要非要Why must you always interrupt me？Can I borrow your car, Mum？If you must. 表示与说话人愿望相反及不耐烦。 情态动词意义 例句 备注 should 应该(常与oughtto通用)You should be polite to the old. ought to 的否定式：ought not to(oughtnt to)；疑问式

9、：Ought to？ 竟然 It is strange that he should react in this way. 表示惊讶、意外等语气。 万一 Should anyone phone, tell them I will call back later. ( If anyone should phone)If I should go there tomorrow, I would go to see her. 用于if从句中强调“万一”，或用于虚拟语气。 3. need, dare 情态动词例句 注意事项 needI neednt go at once. Need you go at

10、once？Yes，I must. /No, I neednt.need可以作实义动词，用于各种句式。如：I need to go at once.I dont need to go at once. Do you need to go at once？Yes，I do.need作情态动词常用于否定、疑问或条件句中。dareHe darent cross the river.How dare you say that to me？dare和need一样，既可以作情态动词，也可用作实义动词。用作情态动词时，主要用于否定句、疑问句和条件句。用作实义动词时，可用于各种句式。如：He didnt dar

11、e (to) go out alone at night. (在否定句中to有时可省略) 4.shall/will/would情态动词意义 例句 备注 shall 表示征询意见。 Shall I help you？ 用于第一、第三人称疑问句中。 表示说话人的意愿，有“命令，允诺，警告，决心”等意思。 You shall do as I say. (命令)You shall have the book tomorrow. (允诺)If you dont get out, I shall knock you down. (警告)用于第二、第三人称。 4.shall/will/would情态动词意义

12、 例句 备注 will/would表示意愿 I will do everything for you. None is so blind as those who wont see. 表请求 Will/ Would you please close the window？ 用于疑问句中。would更委婉 表示某种倾向或习惯性动作 Fish will die without water. Every time she was in trouble，she would turn to him for help. (would指过去某一段时间的情况，常与表示过去的时间状语连用，意为“总是，总会”，后

13、面只能接动作性的动词。) used to表示与现在的情况相反，表示“过去如此而现在不再这样”。其后既可接表动作的动词，也可接表状态的动词。如：There used to be an apple tree in front of the house.4.shall/will/would情态动词意义 例句 备注 will/would表示功能(能，行) If you dont have a pen, a pencil will do.We tried the door again，but it wouldnt open. 与否定词连用常表示“拒绝”。 表示推测(可能、大概) This will be

14、 the house you are looking for. I would be about ten when my father left home.二、 情态动词have done 情态动词意义 例句 备注 must have done；may/might have done；can/could have done一定(肯定句)；可能(肯定句和否定句)；可能(疑问句和否定句)You cant/couldnt have met my grandmother. She died before you were born. 对过去的事情的推测 might have done; couldha

15、ve done；would have done本来可能做而未做；本可以做而未做；本来会做而未做He might have given you more help, even though he was very busy.We could have walked there, and it was so near.与过去事实相反的虚拟表达 情态动词意义 例句 备注 should/ought to have done本应该做而未做 Your brother has failed English exam again. You ought to have given him more help.

16、表示责备neednt have done本不需要做但却做了You neednt have wakened me up; I dont have to go to work today.四、虚拟语气 虚拟语气表示说话人所说的话不是事实，而是一种假设、愿望、怀疑或推测。1 虚拟语气在条件句中的用法 if从句主句与现在事实相反if主语动词过去式主语should/would/could/might动词原形与过去事实相反If 主语had过去分词主语should/would/could/might have 过去分词与将来事实相反(1) if主语动词过去式主语should/would/could/ mig

17、ht动词原形(2)if主语were to动词原形(3) if主语should动词原形If it were to rain tomorrow, I should not drive my car. 如果明天下雨的话，我就不开车了。(明天的情况还不知道) If I had done it in time, I should have had a good time. 如果我及时做的话，日子就好过多了。(可惜当时没能及时做) 注意：(1) 主句中的should通常用于第一人称，would可用于任何人称。(2) 条件句中如果动词是be，其过去式所有人称的单复数都可用were；在第一、三人称单数的口语中

18、，可用was代替were。但在if I were you中，不能说成if I was you。(3) 当条件从句的行为与主句所表示的行为所发生的时间不一致时，主从句中动词的形式要根据它所标示的时间作出相应的调整，这就是所谓的“错综条件虚拟语气”。如： If they had studied hard, they could do it easily now. 如果他们以前努力学习的话，现在干得就会容易些了。 If he had not taken my advice, he wouldnt do it much better like this. 如果他不听我的建议，他就不会干得这么好了。(4

19、) 在条件句中，如果有were, had, should等，则可省略if，但应注意把were, had, should等提到从句主语之前。如：If he were to come, I would join him in the discussion. Were he to come, I would join him in the discussion. 如果他来，我将和他一道参加讨论。(5) 有些虚拟条件句没有从句，虚拟条件句是通过上下文或介词短语表示出来的。如： But for air and water, there would be no life on the earth. 要是没

20、有空气和水，地球上就没有生命。(介词短语but for提供了虚拟条件) With your help, we might finish the plan earlier. 要是有你的帮助，我们就可以早些完成任务。(介词短语with your help充当虚拟条件句)2 虚拟语气在wish从句中的用法专题八 正面解读宾语从句愿望I wish主语动词过去式现在不能实现的愿望主语had过去分词过去不能实现的愿望主语would/might动词原形将来不能实现的愿望I wish I were a doctor. 我希望我是个医生就好了。(现在) I wish that the rain would st

21、op. 我希望雨能停下来。(将来) I wish that he had not made so much fuss about it. 我希望他不要把事情搞大了。(过去)3 虚拟语气在名词性从句中的使用(1) 在insist；command，order；demand，request，require，desire；advise, propose, suggest，recommend等表示“命令、要求、建议”的动词后接的宾语从句中要使用虚拟语气。如： He suggests that she (should) leave the house at once. 他要她立刻离开这所房子。He pro

22、posed that we (should) deal with the problem by the view of development. 他建议我们应该用发展的眼光处理这个问题。(2) 与上述动词相对应的名词suggestion, order, demand , proposal 等后的表语从句、同位语从句中也要使用虚拟语气(should可省略)。如： My proposal is that we (should) set a deadline for handing in the plan. 我的建议是为这个计划设定一个上交的期限。(3) 在It be suggested (orde

23、red, demanded, proposed, )that 结构中，主语从句中也要使用虚拟语气。如： Its required that every student be on time for school. 要求每个学生准时到校。(4) 在do you suggest/recommend用在特殊疑问句中作插入语时，句子的动词也使用虚拟语气，即“should动词原形”的形式，其中should可以省略。如： What type of computer do you recommend/ suggest we (should) buy? 你建议我们买什么类型的电脑呢？(5) 在Itsneces

24、sary，essential，important, strange, natural等形容词 that从句或Its a pity，a shame等名词 that 从句中，谓语动词可以使用should do。如： It is necessary that the badly wounded man should be treated immediately. 这位重伤员必须马上治疗。 Its a pity that you should be so careless. 你竟然如此粗心，真是可惜。4 虚拟语气在状语从句中的用法 在as if/though引导的状语从句中，谓语动词用过去式表示与现在

25、相反的情况；用过去完成式，表示与过去相反的情况等。其变化与wish后的宾语从句的变化相同。如： Ive loved you as if you were my relative. 我一直爱你仿佛你是我的亲人。5 虚拟语气在其他一些句型中的用法(1) Its high time that从句中，谓语动词可以使用过去式，也可使用should动词原形；表示“早该了”，其中should不可省略。如： Its high time we got up/should get up. 我们早该起床了。(2) would rather从句中，谓语动词用过去式表示与现在或将来的情况相反；用过去完成式，表示与过去的

26、情况相反。如： I would rather you came tomorrow. 我宁愿你明天来。(3) if only要是多好啊。如： If only you hadnt offended him. 你当时不惹他就好了。 If only he could come tomorrow. 他明天能来就好了。(4) 其他一些表示祝愿的句型。如： May you succeed！祝你成功！ Long live the Peoples Republic of China. 中华人民共和国万岁！1. 【误】 The streets are all dry; it mustnt have rained

27、last night. 【正】 The streets are all dry; it cant have rained last night. 【解析】 对某一事实的否定推测不能用must，而要用cant 或couldnt表示“不可能”。2 【误】 I didnt see Mary at the meeting yesterday. She might be ill, I guess. 【正】 I didnt see Mary at the meeting yesterday. She might have been ill, I guess. 【解析】 猜的事情发生在昨天，因此要用情态动词

28、have done形式，当动词是be时，很容易忽略它的时态意义，要特别留意。3 【误】 He must be very friendly at times. 【正】 He can be very friendly at times. 【解析】 句意为：他有时会很友好。可知此处并非对现在的状态进行推测，而是一种理论上的可能性，因此用can。4 【误】 I cant find my keys. I may/might forget them on the playground yesterday. 【正】 I cant find my keys. I may/might have left the

29、m on the playground yesterday. 【解析】 表示对过去情况的推测，通常用must/may/might have done sth. 另外，表示“把忘记在某地”应用动词leave。5 【误】 The fire spread through the hotel quickly, but everyone could get out. 【正】 The fire spread through the hotel quickly, but everyone was able to get out. 【解析】 表示在过去成功地做到了某事，肯定句中通常用was/were able

30、 to do sth.。6 【误】 Will I open the window for you? 【正】 Shall I open the window for you? 【解析】 shall与第一、第三人称连用，表示征求意见或请求指示，这时不可用will。will通常与第二人称连用，即Will you？7 【误】 The plant is dead. Maybe I should give more water. 【正】 The plant is dead. Maybe I should have given more water. 【解析】 根据第一句可知，植物已经死亡，所以应该是自责：本应该多浇些水的。要用should have done形式表示“本应该做而未做”。8 【误】 Ha