1、,情态动词 modal verbs,can could may might shall should must will would ought to,have to dare (darent) need (neednt) used to,表示推测,不表示推测,modal verbs,1. To talk about ability（能力） 2. To talk about obligation（义务） 3. To talk about certainty（可能性） 4. To talk about permission（允许） 5. To make requests（提出请求） 6. To
2、make suggestions（提出建议） 7. To make offers（提供帮助） 8. To give advice（提出建议）,不表示推测时,注意以下用法：,Note 2,Note 1,Modal verbs,ability,certainty,permission,obligation,make requests,make suggestions,make offers,give advice,能力,义务,肯定性,允许,提出请求,提出建议,提供帮忙,提出意见,情态动词表示能力的用法,1. 情态动词表示能力时，一般用cancould或be able to,注意：be able t
3、o用于表示能力并且可用于各种时态(am/is/are able to; was/were able to; have/has been able to; shall be able to -) ，而can只有一般现在时和一般过去时两种时态。 e.g. We shall be able to finish the work next week.,was / were able to : “设法做成某事”，相当于managed to do sth. ；succeeded in doing sth. e.g. All the people trapped in the burning house w
4、ere able to get out of it.,2. can常指现在，较常用；如果只表示能力时，两者都可用,I can/am able to swim.,3. can 客观上能够；be able to 更侧重于“克服一定困难”“经过一定努力”“有能力”干某事,The fire spread through the hotel very quickly but everyone _get out A had to B would C could D was able to,To talk about obligation,ought to/should have to musthave t
5、o 能用于各种时态,且有人称和数的变化, dont have to, had to, has toought to 的否定式为ought not to/oughtnt to,强,情态动词表示义务的用法,might may should ought to will must,强,To talk about uncertainty,情态动词表示可能性的用法,may / might, can / could * might, could 比较委婉, 一般多用于疑问句. * can, may 表达的语言比较随便. * 在以could, might 表示征询对方意见或表示请求时，回答应相应使用can,
6、may.,To talk about permission,情态动词表示允许的用法,情态动词表示“许可”的用法,cancould/may/might,过去式could常用于疑问句中，比can更加委婉表示礼貌。回答时，常用原形can或者may，不可再用过去式could/might。,-Can/May/Could I use your pen?,肯定简略回答：-Yes, you can/may.-Yes, please.,否定回答：-No, you mustnt/cant. -Please dont. -No, you may not.,其它情态动词的用法,Shall 和 Should,1). s
7、hall用于第一、三人称疑问句中，表示说话人征求对方的意见和向对方请示。,Shall we begin our class?（征求意见）,When shall Mike be able to leave hospital?(请示),2). shall 用于第二、三人称陈述句中，表示说话人给对方的命令，警告，允诺，决心或威胁。,1.You shall go with me.(命令),2.You shall have the book when I finish it.(允诺),3.He shall be punished.(威胁),3). 用于条约，规定，规章等文件中，表示一种义务，多用于第三人
8、称中。,“The interest _be divided into five parts, according to the agreement made by both sides.” declared the judge. may B. should C. must D. shall,D,4) ought to/should,1.表示义务，“应该”，用于各种人称 You should be polite to your teacher. You shouldnt spend so much time playing computer games. 2.表示推测，“想必，估计”的意思 If
9、 they start today, they should arrive there in two days. 3.表示与想象的不一样”照说应该” I wonder where Mary is. she should be here now.,4.在某些从句中，表示虚拟语气 He suggested that I (should) go to shanghai tomorrow. He demanded that we (should) solve the problem at once. 5.表示惊讶，忧虑，惋惜等感情色彩 I am surprised he should eat so l
10、ittle every day.,should = ought to 表示劝告，命令，建议，意为“应该”，而ought to 语气更强,A: Ill start the work tomorrow.B: I think you should start today.C: No, you ought to start at once.(语气更强）,比较： should ought to,比较： must have to,must 必须，侧重说话人的主观看法,have to (有多种时态）侧重于客观上的需要，含有“不得不”的意思have got to,- Must I hand in my exe
11、rcises now?,- Yes, you must. (No, you neednt. No, you dont have to.),注意：,mustnt 不应该，不许，禁止,neednt 不必,dont have to,1. will表请求，建议等，不如would委婉,Will /Would you pass me the book? Will he pay for me?,2. will 表示意志，愿望，决心,I will never do that again.,I will give up smoking.,Will 做情态动词,比较：shall will,shall表达诺言;wi
12、ll表示决心或决定 Dont worry. You shall have the tickets for the games. Liu Mei will go and buy the tickets for the games.,比较： used to would,1.都可以表示过去重复的习惯，used to 含有“过去怎样而现在却不这样了”的意思；而would则单纯表示过去的习惯性动作，常和often, every day等连用。,He would take a walk near the forest in the evening. （现在可能散步也可能不散步了）,He used to t
13、ake a walk near the forest in the evening. （而现在不散步了）,比较：mustnt neednt,mustnt “不准，不许” 语气强烈 neednt “不需要，没必要” 语气缓和 You mustnt miss this football match. Its very important. You neednt watch the game if you dont want to. Must we clean the classroom? Yes, you must. /No, you neednt.,比较：need dare,作为情态动词时，两个
14、词常用于疑问句和否定句；用作实义动词时，可用于各种句式 情态动词时： -Need I help you? -Yes, please. You neednt telephone him now. How dare you talk to the teacher like that? The girl dare not go out alone at night.,用作实义动词时,We need to tell him the news. You dont need to tell him the news. Do the flowers need watering? I didnt dare t
15、o tell you the truth. Would you dare to catch the snake with your hand? The boy dares to do anything he likes.,1. She isnt what she used to be. 她跟过去不一样了。 （表示对比，不可用would）,2. There used to be a park. 以前这里有一个公园。 表示过去的状态，只能用 used to，不可用would。,2.不能用would的情况,情态动词 (+动词原形),行为动词,.,need,dare,1.无人称和数的变化;,2.尤其用
16、于：,*否定句及疑问句中;,*在if/whether之后;,*或与hardly, never, no one, nobody连用;,3.常以neednt和darent 的形式出现;,4.dare有其过去时dared.,多用于肯定句;need to dodare to do need to be doneneed doing,可兼做行为动词的情态动词,Modal Verbs,-Need I help you? -Yes, please.You neednt telephone him now.How dare you talk to the teacher like that? The girl
17、 dare not go out alone at night.,Ordinary Verbs,We need to tell him the news. You dont need to tell him the news. Do the flowers need watering?I didnt dare to tell you the truth. Would you dare to catch the snake with your hand? The boy dares to do anything he likes.,1 情态动词表示推测的用法,情态动词must，can，could
18、，may，might都可用来表示推测,must所表示的可能性最大，最有把握，意为“一定”。,can和could主要用于否定句和疑问句中 ，cant或couldnt 表示“不可能”,may 和 might表示现在或将来可能发生的动作或情况，主要用于肯定句中，might相对于may 来说， 表示的可能性更小一些。,注意：,1).表示猜测，can/could一般不用于肯定句中，除非是“经验之谈”。 如：Anybody can make mistakes 2)may和might都不用于疑问句中。 如：（正）Can Could it be cloudy tomorrow ？（误）May Might it
19、 be cloudy tomorrow ？,should也可表示“推测”，意为“可能；该”, 相当于be expected to。往往指具有一定的客观根据或根据推理对现在某事发生的“可能性”进行描述，语气上不如must强。,1. Will Mr Wang offer us a hand？ He_ be glad toHe never refused our requestAcan Bmust C may Dshould,D,1.表示对现在或将来情况的推测、判断用“must + do ”2.表示对过去的情况或已经发生的事情进行推测、判断用“must + have +done”3.表示对现在或过去
20、正在进行情况进行推测、判断用“must + be +doing ”,表示推测情态动词的重要用法,肯定的推测可能的推测否定的推测疑问的推测,must,对将来 对现在 对过去,情态动词,may, might could, can,cant, couldnt,can, could,+ V. + V. + have done 常见must be + be doing,+ V. + V. + have done+ be doing,+V. + V. + have done+ be doing,+ V. + V. + have done+ be doing,表示推测情态动词的重要用法.,否定的情态动词的用
21、法:,mustnt 不准, 禁止 neednt 没必要 ( = dont have to ) cant 不能; 不可能 may not 不可以; 可能不 shouldnt 不应该 ( = ought not to ) shant 禁止 darent 不敢,must have done 的反意疑问句,You must have seen the film, havent you? You must have seen the film last week, didnt you? His parents must have beaten him, havent they? His parents
22、must have beaten him yesterday, didnt they?,1.那小女孩没有出门.她现在一定在做家庭作业。 2.路上是湿的。昨晚一定下雨了。 3.我刚刚拜访过他。他现在一定呆在家里。 4.你为什么没有接电话？我当时一定是在睡觉， 5.那男孩想必已经完成了他的家庭作业了,1. The girl is not out. She must be doing her homework now. 2. The road is wet. It must have rained last night. 3. I have just dropped in on him. He mu
23、st stay at home. 4. Why didnt you answer my phone call? Well, I must be sleeping, so I didnt hear it. 5. The boy must have finished his homework.,He is at home. (事实) He must be at home.（非常肯定的推断） He could be at home.（很可能） He ought to be at home.（很可能） He may be at home.（仅仅可能而已） He might be at home.（或许
24、, 非常不确定） He might not be at home.（也许不在家） He may not be at home. （比might可能） He couldnt be at home.（很可能不在家） He cant be at home.（一定不在家） He isnt at home.（事实）,解答情态动词表示猜测的试题时，一要清楚被猜测的时间，二要清楚有无客观事实根据。若有客观事实根据，则无论是肯定还是否定的猜测，猜测语气最强且符合时间要求的为最佳答案；若无客观事实根据，纯凭主观臆断则猜测语气最弱且符合时间要求的为最佳答案。 情态动词表示猜测时语气从强到弱的顺序是：must，should，can，may，could，might。,1“should ought to 完成式” “本应当做某事，而实际上并没有做”； “shouldnt oughtnt to完成式” “本来不应当做，而实际上却做了”。 2.“maymight 完成式” “本来可以干某事却没有干”，突出其可能性；而 “could 完成式” “本来能够做某事，但实际上却没有做”。 3.“neednt 完成式” “本来没必要做某事，实际上却做了,情态动词在虚拟语气中的用法,
