湖南省衡南县第九中学高考英语 语法专题复习 情态动词和虚拟语气

情态动词和虚拟语气 二、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，多半不是事实，或与事实相反。 高考重点要求： 1、情态动词的基本用法 2、情态动词表示推测的语义差别 3、情态动词后接不定式完成体的不同意义 4、虚拟语气中情态动词的用法 情态动词 (一) 情态动词在一般时否定句中的用法 can't(cannot) 表示“不可能”， may not 表示“不可以”， mustn't(must not) 表示“一定不要”，“不许可”，needn't (need not) 表示“不必”，dare not ＋动词原形表示“不敢”。 He can't know the news. He may not sleep now. You mustn't criticize her in that way. You needn't come tomorrow. He dared not meet his parents. （二）can，may，must三者用法比较 can，may，must是三个最重要的情态动词，其基本句型如下： 肯定句：主语+can，may，must +动词原形 否定句：主语+can，may，must +not +动词原形 疑问句：Can，May，Must +主语+动词原形 1. can，may，must的肯定句 You may eat lunch，but you must wash your hands.  你可以吃饭，但是你必须洗手。 （1）can 表示能力；能，会  She can run fast，but I can't.  她很会跑，但是我不会。 表示可能；能够  I can get there in ten minutes. 我十分钟之后就可以到那儿。（表示一种可能性） 表示允许；许可  You can use this dictionary.  你可以用这本字典。 can和be able to比较 can只有现在式和过去式，而be able to可以用于各种时态。 can（could）表示能力时，可用be able to代替。 I can（=am able to）pay for the book.           我买得起那本。 He will be able to tell you the news soon.         他很快就能告诉你消息了。 She has been able to come to school.              她已经能去学校了。 （2）may 表示请求、许可  May I borrow your pen？  我可以借你的钢笔用一用吗？ 可能、或许      Tomorrow I may go shopping.  明天，我可能（或许）去商店买东西。 He might be our new teacher.  他或许是我们的新老师。 （3）must 必须、应该（表示有做某一动作的必要或义务） You must buy a ticket.  你必须买一张票。 一定、准是（表示有把握的判断或推测，一般只用于肯定句中） He must be our new teacher. 他肯定是我们的新老师。 表示推测的用法 can , could ,may ,might ,must 皆可用来表示推测，其用法如下： could ,might 表示推测时不表示时态，其推测的程度不如can ,may。 can ,could 用于否定句和疑问句中。 句型：主语+ can't , couldn't +be +v-ing．（否定句） Can ,Could +主语 +be +v-ing．（疑问句） They can't be cleaning the room now．他们现在不可能在打扫房间。 may ,might , must 用在肯定句中。 句型：主语+ may ,might ,must +be +动词 -ing  （表示对现在发生动作的推测） He must be sleeping . 他现在肯定在睡觉。 must /can't…  + have +过去分词则指对过去已发生的事进行推测。 The road is wet. It must have rained last night . 地是湿的；昨天晚上肯定下雨了。 There isn't any water on the road . It (can't ) couldn't have rained last night . You must have seen the film,______________ you? (三) have to的用法 1. have（has）to +动词原形 have（has）to后面要用动词原形。当主语为第三人称单数时用has to，当句子是过去时用had to。 We have to leave now. He has to work on Sunday. I had to do my homework last Sunday. 2. have to的否定句 句型：主语+don't（doesn't, didn’t, will not）have to+动词原形 You don't have to walk so fast. He will not have to buy a new coat next year. 3. have to的疑问句 你现在必须学数字吗？  ___________________________________________ . Yes，I __________________.      No，I _________ _______（have to）。 他非要问那个问吗？  Did he have to ask the question？ Yes，he did.              No，he didn't（have to） 4. must与have to比较 must侧重于个人意志和主观上的必要，have to侧重于客观上的必要。如果用于过去时态或将来时态时，则要用have to的相应时态来代替must。但must可用于间接引语中表示过去的必要或义务。 My brother was very ill，so I _____________call for the doctor in the middle of the night. I haven't got any money with me，so I'll have to borrow some from my friend. He said that they must work hard.他说他们必须努力工作。 (四). used to do sth 的用法 注意其否定句和疑问句的结构。 There used to be a lot of trees here,____________________ ? 虚拟语气 虚拟语气表示说话人的意愿、假设、猜测或建议。虚拟语气不表示客观存在的事实，谓语动词用特殊的形式表示虚拟语气。 1． 表示与现在事实相反时的谓语形式。 从句 主句 过去式 (be和were) would (should、could)+ 动词原形     例如：If Tom were hungry, he would eat the bread. (In fact, Tom isn’t hungry.) 2． 表示与过去事实相反的谓语形式。 从句 主句 had + 过去分词 would (should、could) + have +过去分词     例如：If I had left a little earlier, I would have caught the early bus. (In fact, I didn’t catch the bus.) 3． 表示与将来事实相反的谓语形式。 从句 主句 动词过去式 should + 动词原形 were to + 动词原形 would (should、could) + 动词原形     例如：If they came tomorrow, we would told them about it. (In fact, they won’t come tomorrow。) 4． 动词wish后的宾语从句中，谓语动词可用过去式、过去完成式或would、might加原形。 例如：I wish I were as strong as you. He wished I would stay with us. She wished I had attended the meeting yesterday. 5． 在有些动词，常见的有：一个“坚持”（insist）,二个“命令”（order,command）,三个“建议”（suggest,advise,propose）,四个“要求”（demand,require,request,ask）后的宾语从句中谓语动词用“should + 动词原形”，should可以省略。例如： He suggested that we (should) discuss the problem right now. 6． 在有些句型中如：It is important (necessary、natural、strange等) + that从句中的谓语动词用should + 动词原形，should可以省略。例如： It is necessary that the doctor (should) be sent there at once. 7． 在It is time that, I would rather that句式中从句谓语动词用过去式。例如： It is time we went to bed. I would rather he came next week. 复习时需注意的要点 （一）情态动词 1、情态动词在句中没有人称和数的变化。 2、含有情态动词的句子改为否定句或疑问句不必加助动词，只需要将情态动词置于主语前，或在情态动词后加上not。 e.g. Must I write a letter to cheer him up? You needn’t wait for me. 3、 情态动词的过去式，例如can—could，may—might。但是少数情态动词只有过去式，例如used to表示过去常常。must的过去式往往用had to代替。 4、 情态动词后还可接不定式的进行式、完成式和被动式。 e.g.He can’t be doing his homework now. He must have attended the meeting last night. （二）虚拟语气 1、 在if条件句中，如果含有were , should或had等助动词，if可以省去，句子用倒装。 e.g. Were I you , I would buy this reference book.(=___________________________________________) 2、 should与would都可以用于if条件句的主句中，但should一般只用于第一人称，would用于所有人称。 e.g. If you were here , I would tell you the news . 3、 某些条件可以用介词短语without… , but for 等来表示 。 e.g. Without your help , I could not have succeeded in passing the exam . 4、 有时句子通过but或otherwise等词来表示真实与虚拟的转换，在这种情况下，只有不 真实的部分用虚拟式。 e.g. I was ill yesterday；otherwise I would have played football with you . But for the heavy rain , we would have gone to the concert . 5、 有suggest等词的相应的名词组成的同位语从句及表语从句用虚拟式。 e.g. I accepted my mother’s suggestion that I should eat an apple every day . 二、历届高考试题分析 1、There ____ be any difficulty about passing the road test since you have practised a lot in the driving school. A. mustn’t         B. shan’t             C. shouldn’t         D. needn’t 2、—Is John coming by train?    —He should, but he _______ not. He likes driving his car. A. must      B. can        C. need        D. may 3、It is hard for me to imagine what I would be doing today if I _______ in love, at the age of seven, with the Melinda Cox Library in my hometown. A. wouldn't have fallen      B. had not fallen    C. should fall      D. were to fall 4、You can't imagine that a well-beha ved gentleman ________be so rude to a lady. A. might                  B. need          C. should            D. would 5、What would have happened ________, as far as up to the river bank? A. Bob had walked farther  B. if Bob should walk fartherC. had Bob walked farther  D. if Bob walked farther 6、Mr. Bush is on tim e for everything. How ________it be that he was late for the opening ceremony? A. can        B. should      C. may      D. must 7、My sister met him at the Grand Theatre yesterday afternoon, so he _________ your lecture. A. couldn't have attended  B. needn't have attendedC. mustn't have attended    D. shouldn't have attended 8、He hesitated for a moment before kicking the ball, otherwise he_________ a goal. A. had scored    B. scored        C. would score      D. would have scored 9、Oh, I'm not feeling well in the stomach. I _______ so much fried chicken just now. A. shouldn't eat  B. mustn't have eaten    C. shouldn't have eaten  D. mustn't eaten 10、I was really anxious about you .You_________ home without a word. A. mustn't leave  B. shouldn't have left    C. couldn't have left  D. needn't leave 巩固练习 1. —Isn' t that Ann's husband over there? —No, it _______ be him . I'm sure he doesn't wear glasses. A. can't         B. must not          C. won't              D. may not 2.You    　   to the meeting this afternoon if you have something important to do.　 A. needn't to come　    B. don't need come  C. don't need coming      D. needn't come 3. He    　you more help, even though he was very busy.    A. might have given  B. might give    C. may have given  　D. may give 4. The reason why they     　　leave wasn't explained to us.　 A. had          B. had to      C. must              D. might 5. I searched for my wallet and it wasn't there. I thought I    　it at home.                                        　 A. left  　        B. have left         C. might have left      D. could have left 6. I 　________ asleep because it took me a long time to realize that the telephone was ringing.                                    A. could have fallen     B. should have fallen  C. must have fallen  D. mustn't have fallen 7. The only thing that really matters to the children is how soon they   　return to their school.                         　 A. can          B. must          C. have to          D. ought to 8. I want to go to the chemist's, but you     　　go with me.　 A. need not      B. must not      C. need              D. can’t 9. What we     　　get seems better than what we have.    　 A. can          B. could          C. can't              D. couldn't 10. —My goodness! I've just missed the train. —That's too bad. I am sure you     　　it, if you had hurried. A. could have caught 　     B. had caught  C. would catch   　D. could catch 11. Look! What you've done! You   　　more careful.        　 A. may be 　    B. had to            C. should have been     D. would be 12.     　　I repeat the question?                  A. S hall 　     B. Will 　         C. Do you want that 　    D. Do 13. Professor Li, many students want to see you.     　　they wait here or outside!                                            A. Do          B. Will          C. Shall              D. Are