1、情态动词 情态动词定义:情态动词是一种本身有一定的词义,但要与动词原形一起使用，给谓语动词增添情态色彩，表示说话人对有关行为或事物的态度和看法，认为其可能、应该或必要等。情态动词后面加动词原形。 分类：情态动词有四类：只做情态动词：must,can(could),may(might),ought to可做情态动词又可做实义动词：need,dare可做情态动词又可做助动词：shall(should),will(would)具有情态动词特征：have(had) to,used to 位置:情态动词在句中放在谓语动词之前, 谓语动词前若有助动词,则在助动词之前,疑问句中, 情态动词则在主语之前。 I
2、 can see you. Come here. 我能看见你，过来吧。 He must have been away. 他一定走了。 What can I do for you? 我能帮你吗？How dare you treat us like that！ 你怎能那样对待我们！ 特点:情态动词无人称和数的变化, 情态动词后面跟的动词需用原形,否定式构成是在情态动词后面加 not。 个别情态动词有现在式和过去式两种形式, 过去式用来表达更加客气, 委婉的语气, 时态性不强, 可用于过去，现在或将来。情态动词属非及物动词，故没有被动语态。情态动词没有非谓语形式，即没有不定式，分词，等形式。 He
3、could be here soon. 他很快就来。 We cant carry the heavy box. 我们搬不动那箱子。 Im sorry I cant help you. 对不起，我帮不上你。 基本助动词与情态助动词最主要的区别之一是，基本助动词本身没有词义，而情态助动词则有自己的词义，能表示说话人对有关动作或状态的看法，或表示主观设想： What have you been doing since? （构成完成进行体，本身无词义） I am afraid I must be going. （一定要） You may have read some account of the ma
4、tter. （或许已经） 除此之外，情态助动词还有如下词法和句法特征： 1） 除ought和used以外，其他情态动词后面只能接不带to的不定式。如果我们把ought to和used to看做是固定词组的话，那么，所有情态动词无一例外地只能接不带to的不定式： We used to grow beautiful roses. I asked if he would come and repair my television set. 2） 情态助动词在限定动词词组总是位居第一： They need not have been punished so severely. 3） 情态助动词用于第三
5、人称单数现在时的时候，没有词形变化，即其词尾无-s形式： She dare not say what she thinks. 4） 情态动词没有非限定形式，即没有不定式和分词形式，也没有相应的动名词： Still, she neednt have run away. 5） 情态助动词的“时”的形式并不是时间区别的主要标志。在不少场合，情态助动词的现在时和过去时形式都可以表示现在、过去或将来时间： Would you mind very much if I ask you to do something? She told him he ought not to have done it. 6）
6、 情态助动词之间是相互排斥的，即在一个限定动词词组中只能出现一个情态助动词，但有时却可以与have和be基本助动词连用： You should have washed the wound. Well, you shouldnt be reading a novel. 用法首先它是动词，而且不同于行为动词，行为动词表示的是可以通过行为来表达的动作（如写，读，跑），而情态动词只是表达的一种想法（如能，也许，敢）。用法是：情态动词+行为动词原形 例句：I can read this sentence in English. 我能用英语读这句话。 情态动词是一种本身有一定的词义,表示说话人的情绪,态度
7、或语气的动词,但不能单独作谓语, 只能和其他动词原形构成谓语。 We can be there on time tomorrow.我们明天能按时去那儿。 May I have your name? 我能知道你的名字吗？ Shall we begin now?我们现在就开始吗？ You must obey the school rules.你必须遵守校规。情态动词数量不多,但用途广泛,主要有下列: can (could), may (might), must, need, ought to, dare (dared), shall (should), will (would),have (to)
8、 ,had better. 功能助动词(auxiliary)主要有两类：基本助动词(primary auxiliary)和情态助动词(modal auxiliary)。基本助动词有三个：do, have和be；情态助动词有十三个：may, might; can, could; will, would; shall, should; must, need, dare, used to, ought to. 上述两类助动词的共同特征是，在协助主动词构成限定动词词组时，具有作用词的功能： 1） 构成否定式： He didnt go and neither did she. The meeting m
9、ight not start until 5 oclock. 2） 构成疑问式或附加疑问式： Must you leave right now? You have been learning French for 5 years, havent you? 3） 构成修辞倒装： Nowhere can he obtain any information about his sister. Hardly had he arrived when she started complaining. 4） 代替限定动词词组： A: Who can solve this crossword puzzle?
10、B: Tom can. A: Shall I write to him? B: Yes, do. 情态动词的用法要点一 can和could情态动词用法例句can/could表示能力（体力、知识、技能）(表示过去有能力用could)1“I dont think Mike can type.” 2I can speak fluent English now , but I couldnt last year.3Can you lift this heavy box?（体力） 4Mary can speak three languages.（知识） 5Can you skate?（技能）6.Two
11、eyes can see more than one. 两只眼比一只眼看得清。 7.Could the girl read before she went to school? 这女孩上学前能识字吗？在肯定句中，表示客观可能性，（客观原因形成的能力）。并不涉及具体某事会发生，常用来说明人或事物的特征。要表达具体某事实际发生的可能性时，不用can，需用could，may，might。1 As a human being, anyone can make a mistake.2 Im confident that a solution can be found.3 He can be very f
12、orgetful sometimes.4 I may stay at home this weekend.（实际可能性）5 Peter might come to join us.(实际可能性) 6 It will be sunny in the daytime ,but it could rain tonight.(实际可能性)7 7.Theyve changed the timetable, so we can go by bus instead. 8 8.This hall can hold 500 people at least. 9 The temperature can fall
13、to 60, that is 60 below freezing. 气温可降至60，也就是零下60。 10 11.He cant (couldnt) have enough money for a new car. 他不可能有足够的钱买新车。 11 12 You mustnt smoke while youre walking around in the wood. You could start a fire. （实际可能性）12 在林子里走时勿吸烟，那样可能会引起火灾。 表示请求和允许。表示请求，口语中常用could代替can，使语气更委婉。用can和 may来回答，不能用could或mi
14、ght。1.Can we turn the air conditioner on?2.Any police officer can insist on seeing a drivers license.3.In soccer, you cant touch the ball with your hands.4.Could you have her call me back when she gets home, please?5.I wonder if I could just ask you to sign this.6. Could I borrow your dictionary? -Y
15、es, of course, you can.No, Im afraid not/No,you cannt/No,you may not.表示对现在的动作或状态进行主观的猜测，主要用在否定句和疑问句中。1 It cant be easy caring for a man and a child who are not your own.2 Can the man over there be our head master?3.If Tom didnt leave here until five oclock, he cant be home yet. 如果汤姆五点才离开这儿，他此时一定还未到家
16、。 表示惊异、怀疑、不相信等态度，主要用在否定句、疑问句和感叹句中。1 Can this be an excuse for not giving them help?2 This cant be true.3 How can you be so crazy.4 4.Can this be true? 5 5.How can you be so careless! 6 6.This cannot be done by him. 7 Where can (could) they have gone to? 他们会去哪儿了呢？ 8 He cant (couldnt) be over sixty. 他
17、不可能超过六十岁。 9 How can you be so careless? 你怎么这么粗心？10 特别说明：（1） could用来表示请求时，语气委婉，主要用于疑问句，不能用于肯定句，答语应用can（即：could不能用于现在时态的简略答语中）。如：Could I use your dictionary?Yes, you can.(否定回答可用：No, Im afraid not.)此时可与may互换。在疑问句中还可用could, might代替，不是过去式，只是语气更委婉，不能用于肯定句和答语中。 - Could I come to see you tomorrow? - Yes, yo
18、u can. ( No, Im afraid not. ) (2) can和be able to辨析can(could)和be able to都可以表示能力，意思上没有区别。但can只有现在式和过去式，而be able to则有更多的形式。如：Ive always wanted to able to speak fluent English.Those bags look really heavy, are you sure youll be able to carry them on your own?但是，表示在过去某时的某一场合经过一番努力，终于做成了某事，通常不用could，而用was
19、/were able to来表示。could：有潜能，但并未做到这时，was/were able to相当于managed to do或succeed in doing。如：After the accident it was a long time before she was able to walk again.The fire was very big, but most people were able to escape from the building.I can sing many English songs.我会唱许多英文歌曲。 We were able to return
20、to our campsite before the heavy rain.我们在下大雨前设法会到了野营地。 He was able to swim across the river and escaped being caught.他游到了河对岸，没有被抓住。在否定句中，can/could与be able to几乎没有什么差别，两者可以互换。例如： She wasnt able to/couldnt cook French dishes.她不会做法国菜。(3) 惯用形式“cannot too”表示“无论怎么也不（过分）”。如： You cannot be too careful.你越小心越好
21、。 惯用形式“cannot but+ 不定式（不带to）”表示“不得不，只好”。如： I cannot but admire her determination.我不得不钦佩你的决心。 二may和 might情态动词用法例句may/might表示允许、请求。否定回答一般用must not/mustnt,表示“禁止、阻止”之意，但也可以用had better not (最好别)或may not（不可以），语气较为委婉。 1 May I come in and wait?2 May I smoke here?No, you mustnt(或No, youd better not.)在表示请求、允许
22、时，might比may语气更委婉些。而不是过去式，用May I征询对方许可在文体上比较正式，在口气上比较客气，在日常用语中，用Can I征询对方意见更为常见。否定回答时可用cant 或mustnt，表示“不可以，禁止”。或者肯定回答可以用 yes,please. / Certainly.1.Might I borrow your pen?2.I wonder if I might speak to your son.3 Might/ May I smoke in this room? 4 - No, you mustnt. 5 4. May/Might I take this book out
23、 of the room? - Yes, you can. (No, you cant / mustnt. ) You may drive the car. Might I use your pen? No, you mustnt. 表示可能性的推测，通常用在肯定句和否定句中，含有“或许”“大概”“可能”之意；用might代替may时，则语气显得更加不肯定。1 It may rain this afternoon.2 She might come to join us this afternoon.3 I suppose he might have missed the train.4.He
24、may /might be very busy now. 5Your mother may /might not know the truth. may用于祈使句表示祝愿1 May you succeed.。2 May you have many more days as happy as this one.3 May she rest in peace.愿她安息。惯用句式：“may well+ 动词原形”，意为“完全能，很可能”，相当于to be very likely to“may as well或might(just)as well+动词原形”意为“最好，满可以，倒不如,不妨,”，相当于
25、“had better或there is no reason to do anything else.1 It may well change forever the way you look at Greek art.2 There may well be a real problem here.3 There is nothing to do, so I may as well go to bed.4 You may as well tell us now, well find out sooner or later.5 I suppose we might as well go home
26、.6 And if you have to plough the field anyway, you might as well plant it at the same time.7.If that is the case, we may as well try. might间接引语中指过去。表可以。1. He told me that I might smoke in the room. 他告诉我可以在房间里抽烟。 二must和have to情态动词用法例句must表示“必须，应该，一定”之意，语气比should，ought to强烈。其否定形式mustnt表示“不准，不应该，禁止”等意.
27、1 You must come to school on time.2 Everybody must obey the law.3 You mustnt drive so fast in the street.4 We mustnt waste any more time.5 I must finish my work today.6 Must I return the book tomorrow?7 7.The play is not interesting. I really must go now. 在回答带有must的问句时，否定回答常用neednt或dont have to，表示“不
28、必”，而不用mustnt.1Must I come back before ten? Yes，you must.(No, you neednt)2.Must we hand in our exercise books today? Yes, you must. (No, you dont have to.)表示有把握的推测，意为“一定、准是、想必”，只用于肯定句中。它的否定或疑问式用can代替must1 This must be your pen. 2 You must be hungry after a walk.3 There must be a hole in the wall. 4 Y
29、oure Toms good friend, so you must know what he likes best. 5 5.Your mother must be waiting for you now. 6 He must be staying there. 7 他现在肯定呆在那里。 试比较和第一种用法的区别He must stay there. 他必须呆在那。have to也可拼做have got to。 8 “必须，不得不”，意义与must相近。但must表示的是说话人的主观看法，而have to则往往强调客观需要,有被动接受的意思。无疑问句形式，疑问句用must 代替。910 Th
30、e film is not interesting. I really must go now.11 I have to go now, because my mother is in hospital.12 My brother was very ill, so I had to call the doctor in the middle of the night. 我弟弟病得很厉害，我只得半夜里把医生请来。(客观上需要做这件事) 13 4. Must I clean all the room?14 5. I must go over the test paper again to see
31、if there are any mistakes.我必须再检查一遍试卷看看是否有错误。15 6. The teacher said that there were many mistakes in my test paper, so I had to go over it again.老师说我试卷中有很多错误，所以我只好再检查一遍。16 must只有一种形式，即现在式与过去式都是一种形式，在间接引语中must可用于表示过去时间.而have to则涉及各种人称、时态等方面的变化形式。 1718 7.I had to work hard when I was your age.19 8.I wi
32、ll have to learn how to use a computer.20 9In order to take the exam, well have to finish the whole book by the end of this month .21 10. told her that she must give up smoking. 我叫她必须戒烟。 22两者的否定意义不同，mustnt表示“禁止，不许”，dont have to表示不必。1 You mustnt go there.2 You dont have to go there.四shall和should情态动词用
33、法例句shall用于第一，三人称构成的疑问句，表示征求对方意见或请求指示1 Shall I open the window?2 Shall we say 6 oclock, then?3 What shall I get for dinner?4.Shall we begin our lesson? 4 5.When shall he be able to leave the hospital?5 Shall the boy wait outside? 让那男孩在外面等吗？ 用于第二、三人称陈述句中，表示说话人给对方的命令、警告、决心、允诺或威胁。1 Dont worry, you shall
34、 get the answer this afternoon.(允诺)2 He shall be sorry for it one day, I tell you. （警告）3 You shall do as I say. (命令)4 If you children dont do as I tell you, you shall not go to the party. (威胁) 5. You shall fail if you dont work hard.(警告) 6. He shall have the book when I finish it.(允诺) 7. He shall be
35、 punished.(威胁) 8.You shall do as I say. 按我说的做。（命令） 9.You shall have my answer tomorrow. 你明天可以得到我的答复。（允诺） 10.He shall be sorry for it one day, I tell you. 有一天他会后悔的，我告诉你。（警告） 11.Nothing shall stop us from carrying out the plan. 什么也不能阻止我们执行这项计划。（决心） should表示劝告或建议，意为“应该”其同义词是ought to；在疑问句中，通常用should代替ou
36、ght to1.What should I do?2.Should I trust him?3.You should read his new book.4. You should go to class right away. 5.Should I open the window?You should be polite to your teachers. 你对老师应该有礼貌。 You shouldnt waste any time. 你不应该浪费时间。 表示推测，用在肯定句中，对现在的情况或可能发生的事的主观推测或期待。意为“想必，大概，或许”1 It should be a nice d
37、ay tomorrow.2 Try phoning Robert, he should be home now.3 He should be around sixty years old.4.The film should be very good as it is starring firstclass actors. 这部新电影是一流演员主演的，估计拍得很好。 5.They should be home by now. 照说他们现在应当已经到家了。 还可以用在if引导的条件句中，表示一件事听起来可能性很小，但也不是完全不可能，相当于“万一”的意思。从句谓语用should+动词原形构成，主句
38、都一定用虚拟语气1 Ask Tom to ring me up if you should see him. (你万一见到汤姆，请让他给我打个电话)2 Should I be free tomorrow, Ill come. (万一我明天有时间，我就过来)3 If things should change suddenly, please let me know. (万一情况突变，请通知我)4. Ask her to ring me up if you should see her. 你万一见到她，请让她给我打个电话。 5. If you should change your mind, pl
39、ease let us know. 万一你改变主意，请通知我们。 6.Should I (If I should) be free tomorrow I will come. 万一我明天有时间，我就来。用于疑问句或感叹句中，表示意外、惊异的情绪，意为“竟会”，与why，what，how，who连用，如果是疑问句。则不需要回答。1 Why should anyone want to marry Tony?2 Dont ask me. How should I know?3.Why should you be so late today? 你几天怎么来得这么晚？ 4. Where is Betty
40、 living? 贝蒂住在哪里？ How should I know? 我怎么会知道呢？ 5.I dont know why you should think that I did it. 我真不知道你凭什么认为这件事是我干的。表示说话人的一种谦逊、客气、委婉的语气。 I should think it would be better to try it again. 我倒是认为最好再试一试。 You are mistaken, I should say. 依我看，你是搞错了。 I should advise you not to do that. 我倒是劝你别这样做。五will和would情
41、态动词用法例句will/would用于表示意志，愿望或意愿。will指现在，would指过去。1 He is the man who will go his own way. (他是个自行其是的人。)2 They said they would meet us at 10:30 at the station.3. I will never do that again. 4. They asked him if he would go abroad. 5.He said he would help me.6.Ill do my best to catch up with them.7.I wil
42、l do anything for you. 我愿为你做任何事。 8.None is so blind as those who wont see. 不愿看的人眼最瞎。 9.If you will read the book, Ill lend it to you. 如果你愿意读这本书，我会把它借给你。 They would not let him in because he was poorly dressed. 他们不让他进去因为他衣着破旧。 I said I would do anything for you. 我说过我愿意为你做任何事。 表示请求、建议等，will接近命令的口气。用wo
43、uld比用will委婉、客气。Would like to do = want to 想要，为固定搭配否定句用will，一般不用would, wont you是一种委婉语气。1 Will you please take a message for him?2 Would you please tell me your telephone number?3.Will / Would you pass me the ball, please? 4 Would you like to go with me? 5. Would you like some cake? 6 Wont you sit dow
44、n? 表示习惯或倾向，意为“总是，惯于”。Will指现在，would指过去。would表示过去习惯时比used to正式，且没有“现已无此习惯”的含义。 used to可表示过去的习惯动作和经常的情况，而would只表示过去的习惯动作,不表示状态和情况。1 Fish will die without water.2 People will talk. (人们总会说闲话。)3 When we worked in the same office, we would often have coffee together.4 During the vacation, he would visit me
45、 every other day. 5 The boy will sit there hour after hour looking at the traffic go by. 那男孩常常坐在那里好几个钟点，看着车辆行人通过。 6.He used to would smoke while writing. 过去他写东西时常抽烟。 7.She used to be fat. 她过去很胖表示推测，意为“很可能，大概”。will表示推测比should把握大，比must把握小。1 These things will happen.2 That will be the messenger ringing.3 It would be about ten oclock when he left home.4 It would be about ten oclock when she left home.表示功能，意为“能，行”。惯用形式：will do/would do表示“解决问题”、
