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1、1,米特洋,初中、高中情态动词入门,2,定义,情态动词是一种本身有一定的词义,但要与动词原形及其被动语态一起使用，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。,注意,3,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,has) to,used to,4,位置:,情态动词在句中放在谓语动词之前, 谓语动
2、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 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！,5,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，
3、故没有被动语态。,He 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。,6,The basic uses of Modal Verbs,7,一、 can, could,1) 表示能力（体力、知识、技能）。,Can you lift this heavy box?（体力）Mary can speak three languages.（知识）Can you skate?（技能）,此时可用be able to代替。（考点一）：Can只有一般现在
4、时和一般过去；而be able to则有更多的时态。Ill not be able to come this afternoon.,当表示（考点二）“经过努力才得以做成功某事”时应用be able to，不能用Can。如：He was able to go to the party yesterday evening in spite of the heavy rain.,8,一、 can, could,2) 表示请求和允许。,-Can I go now? - Yes, you can. / No, you cant.,此时可与may互换。在疑问句中还可用could, might代替，不是过去
5、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, you can. ( No, Im afraid not. ) (考点),9,一、 can, could,3) 表示客观可能性（客观原因形成的能力）。,Theyve changed the timetable, so we can go by bus instead.This hall can hold 500 people at least.,4) 表示推测（惊讶、怀疑、不相信的态度），用于疑问句、否定句和感叹句中。,Can this be true?This
6、cant be done by him.对比：This must be done by him.How can this be true?,10,1. Can,Could 过去式；语气更委婉,Can 表示习惯能力， 而be able to表示经过那里而做成了某事。2. 在否定结构中，二者可以互换。,1.在否定、疑问句中表示“对过去发生行为 的可能性猜测。2. 在肯定句中表示“本来可以做而未做”,The door was lacked. She couldnt have been at home.（推测：）You could have been more careful.（但实事上没有更细致）,
7、11,二、 may, might,1) 表示请求和允许。might比 may语气更委婉，而不是过去式。否定回答时可用（考点一）cant或mustnt，表示“不可以，禁止”。,-Might/ May I smoke in this room? - No, you mustnt.- May/Might I take this book out of the room?- Yes, you can. (No, you cant / mustnt. ),用May I.？征徇对方许可时比较正式和客气，而用Can I.？在口语中更常见。,12,二、 may, might,2）用于祈使句，表示祝愿。 May
8、 you succeed!,3) 表示推测、可能性（不用于疑问句）。might不是过去式，它所表示的可能性比may小。1He may /might be very busy now.2Your mother may /might not know the truth.,13,1. May,Might 过去式；语气更委婉,1.在否定、肯定句中表示对过去动作的推测 “也许是”2. Might+have+p.p表示虚拟，表“劝告、责备之意。”,Eg. 1. She may be still waiting for us. 2. May I come in? 3.May you have a happ
9、y holiday.,Eg. 1. He might have spoken to her yesterday.（委婉推测） 2. You might have told me earlier.（你或许可以早点告诉我，但实事上没有，有责备之意）,14,三、 must, have to,1) 表示必须、必要。,You must come in time.在回答引出的问句时，如果是否定的，(考点一)不能用mustnt（禁止，不准），而用neednt, dont have to（不必）.,- Must we hand in our exercise books today?- Yes, you mu
10、st.- No, you dont have to / you neednt.,15,三、 must, have to,2) must是说话人的主观看法， 而have to则强调客观需要。Must只有一般现在时， have to 有更多的时态形式。,He play isnt interesting, I really must go now.I had to work when I was your age.,3) 表示推测、可能性（只用于肯定的陈述句）,Youre Toms good friend, so you must know what he likes best. Your moth
11、er must be waiting for you now.,16,1. Must,表示肯定的猜测,但只用于肯定句，而mustnt 表示“禁止、不准”,Must表示主观Have to表示客观需求Have got to 多见于口语,3. must + have +p.p,对过去事情的肯定猜测。,Eg. The road is wet. It must have rained last night.,17,四、 shall, should,1) shall 用于第一人称，征求对方的意见。,What shall we do this evening?Shall we go there by bus
12、?,2) shall 用于 (考点一) 第二、三人称，表示说话人给对方的命令、警告、允诺或威胁。1. You shall fail if you dont work hard.(警告)2. He shall have me the book when I finish it.(允诺)3. He shall be punished.(威胁),18,1、Shall /should,shall/should + have +p.p ought to,表示本应该做而未做。,should 过去式 语气更委婉,Eg. You should have been five minutes ago.,2、,2、
13、,19,五、 will, would,1) 表示请求、建议等，would更委婉,Will / Would you pass me the ball, please?,2) 表示意志、愿望和决心。1. I will never do that again.2. They asked him if he would go abroad.,20,五、 will, would,3) would表示过去反复发生的动作或某种倾向。would表示过去习惯时比used to正式，且没有 (考点) “现已无此习惯”的含义。,1. During the vacation, he would visit me ev
14、ery other day.2. The wound would not heal治愈 . 创伤难以愈合 Would 后只能接表示动作的动词。used to 则还可以接表示状态的动词。（考点）He used to be a worker.,4) 表示估计和猜想。 It would be about ten oclock when she left home.,21,Will/ would,1、Would 后只能接表示动作的动词。,2、used to 则还可以接表示状态的动词。Eg. He used to be a worker.,22,六、 dare, need,1) dare作情态动词用时,
15、 常用于疑问句、否定句和条件从句中, 过去式形式为dared。,How dare you say Im unfair?He darent speak English before such a crowd, dare he?If we dared not go there that day， we couldnt get the beautiful flowers.,2) need 作情态动词用时, 常用于疑问句、否定句。在肯定句中一般用must, have to, ought to, should代替。,1You neednt come so early.2. - Need I finish
16、 the work today? - Yes, you must. / No, you neednt.,23,六、 dare, need,3) dare和 need作实义动词用时， 有人称、时态和数的变化。在肯定句中，dare后面常接带to的不定式。在疑问句和否定句中，dare后面可接带to或不带to的不定式。而need后面只能接带to的不定式。,1. I dare to swim across this river.2. He doesnt dare (to) answer.3. He needs to finish his homework today.,24,1、情态动词用于否定、疑问句
17、；条件从句中。 eg. 1. Dare you go here alone? 2. How dare you do such follish things? 3. I wont allow you to swim in the river, even if you dare do it.,Dare / dared,2 、做实意动词后加不定式。 eg. I have never dared to tell him about it.,25,Need /needed,1、情态动词用于否定句，疑问句。,2、实意动词用法似dare,用作不定式。,3、need + not + have +p.p 表示“
18、本来不需要做而做了。,26,七、 should, ought to,1) should, ought to表示“应该”，ought to表示义务或责任，比should语气重。,1. I should help her because she is in trouble.2. You ought to take care of the baby.,2) 表示劝告、建议和命令。should, ought to可通用，但在疑问句中常用should。,1. You should / ought to go to class right away.2. Should I open the window?
19、.,27,七、 should, ought to,3) 表示推测should , ought to (客观推测), must(主观推测)。,1.He must be home by now. (断定他已到家)2.He ought to/should be home by now.(不太肯定)3. This is where the oil must be.(直爽)4. This is where the oil ought to/should be.(含蓄),28,Ought to,1、其否定式为ought not to,2、ought to + have + p.p 表示本来应该做而没有做到
20、。 ought + not+ to have + p.p 表示本不来应该做而实际已做到,You ought to have come here early. You ought not to have cut away the trees around the old building.,29,三点说明,1、情态动词 + v 表示对现在或将来动作的猜测。 情态动词 + have + p.p表示对过去动作的猜测。,2、情态动词的过去式与原形相比，多点礼貌，少点冒昧， 语气更为委婉。,情态动词在一般疑问句中的回答： Can you sing? May I come in? Must I handi
21、n the book now? Need I finish it now?,30,典型错误,1. He mustnt be in the classroom. ( ),cant,2. You might leave the bag on the bag. ( ),might have left,3. You must have seen the film last week, havet you? ( ),didnt you,4. Li ming must have been to Japan, didnt he? ( ),hasnt he,31,米特洋,高中情态动词高考要点,32,八、 情态
22、动词+不定式完成式（have done）,can / could + have done在肯定句中表示“本来可以做而实际上能做某事”，是虚拟语气在疑问句或否定句中表示对过去行为的怀疑或不肯定, 表示推测。,1. You could have done better, but you didnt try your best. （虚拟语气）2. He cant have been to that town.（推测）3. Can he have got the book?（推测）,33,八、 情态动词+不定式完成式（have done）,2) may / might +不定式完成式（have don
23、e） 表示对过去行为的推测。不能用于疑问句中，没有虚拟语气的用法。Might所表示的可能性比may小。,He may not have finished the work . 他可能没有做完那项工作If we had taken the other road, we might have arrived earlier. （条件虚拟） （我们也许会到的更早些）,34,八、 情态动词+不定式完成式（have done）,3）must +不定式完成式（have done） 用于肯定句中，表示对过去行为的推测。意为“一定、想必”。其疑问、否定形式用can，cant代替。参看1) can / coul
24、d + have done表示推测。,You must have seen the film Titanic.He must have been to Shanghai.,must have done sth.肯定已经做了某事（对过去的一种非常肯定的推测） can/could not have done sth.不可能已经做了某事（对过去的一种否定推测） may/might (not) have done sth.也许已经做了某事（对过去的一种大概推测）,推测小结,35,八、 情态动词+不定式完成式（have done）,4）should +不定式完成式（have done）用于肯定句中，表示
25、对过去行为的推测。,表示“本应该做而实际上没有做某事”，其否定式表示某种行为本不该发生却发生了。可以与ought to +不定式完成式（have done）互换。,He should have finished the work by now。,You ought to / should have helped him. (but you didnt.)She shouldnt have taken away my measuring tape测尺 , for I wanted to use it.,36,八、 情态动词+不定式完成式（have done）,5) neednt +不定式完成式（
26、have done） 表示“本来不必做而实际上做了某事”。,6) will +不定式完成式（have done） 主要用于第二、三人称，表示对已完成的动作或事态的推测。,You neednt have watered the flowers, for it is going to rain.,He will have arrived by now.,37,米特洋,情态动词表推测小节,38,一、 对现实、现在推测,1) Must 推测（只用于肯定的陈述句）,He must be at home nowHe must know you.He must be waiting for us now.（
27、现在正在进行的推测）,2)can表示推测（惊讶、怀疑、不相信的态度），用于疑问句、否定句和感叹句中。,Can this be true? This cant be done by him.对比：This must be done by him. How can this be true?,注：must+be doing 表示对现在或将来正在发生的事的推测。According to the weather forecast, it must be snowing tomorrow.,39,一、 对现实、现在推测,3) 表示推测、可能性（不用于疑问句）。 might不是过去式，它所表示的可能性比m
28、ay小。,He may /might be very busy now. Your mother may /might not know the truth.Tom may not know you are here.,4) will表示猜测 “可能，大概”。 That will be the postman ringing. 按铃的可能是邮递员,It would be about ten oclock when she left home. That would be wonderful!,5) would表示估计和猜想。,40,一、 对现实、现在推测,6)表示推测should , ough
29、t to (客观推测), must(主观推测)。,1.He must be home by now. (断定他已到家) 2.He ought to/should be home by now.(不太肯定)3. This is where the oil must be.(直爽) 4. This is where the oil ought to/should be.(含蓄),41,二、 对过去、过去事实推测,1) must + have +p.p对过去事情的肯定猜测,The road is wet. It must have rained last night.,2）can./could +
30、have +p.p .在否定、疑问句中表示“对过去发生行为 的可能性猜测。,The door was lacked. She couldnt have been at home. He cant have been to that town.（推测） Can he have got the book?（推测）,42,二、 对过去、过去事实推测,3) may/might + have +p.p在否定、肯定句中表示对过去动作的推测 “也许是（也许不是）”,He might have spoken to her yesterday.（委婉推测）He might not have known of N
31、ini before.,4）should +have +p.p 用于肯定句中，表示对过去行为的推测。,He should have finished the work by now。,43,二、 对过去、过去事实推测,5) will +不定式完成式（have done)主要用于第二、三人称，表示对已完成的动作或事态的推测。,He will have arrived by now.He will have completed his task by evening.He will have graduated by then.到那时他就已经毕业了。,44,We _ last night, but
32、 we went to the concert instead. No wonder we failed in the quiz this morning.A must have studiedB might studyC should have studiedD would study,45,2. Jenny _ have kept her word. I wonder why she changed her mind.A must B should C need D would3. Michale _ be a policeman, for hes much too short.A nee
33、dnt B cant C should D may4. My sister met him at the Grand Theatre yesterday afternoon, so he _ your lecture.A couldnt have attendedB neednt have attendedC mustnt have attendedD shouldnt have attended,46,5. I got up early that morning, but I _ so because I had no work to do.A mustnt have doneB didnt need to doC neednt have doneD cant have done.6. It must have rained last night,_?7. He must have been to Hong Kong , for he knows a lot, _?8. You must be a writer,_?A mustnt you B are you C must you D arent you,didnt it,hasnt he,47,Bye-bye,
