情态动词讲解课件

单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,*,-Modal Verbs,语法：情态动词,I 情态动词的定义,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。,情态动词数量不多，但用途广泛，主要有：can(could),may(might),must,need,ought to,dare(dared),shall(should),will(would).,II 情态动词的位置,情态动词在句中放在谓语动词之前，谓语动词前假设有助动词，那么在助动词之前，疑问句中，情态动词放在主语之前。,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?你要什么？,How dare you treat us like that!你怎么敢那样对待我们!,情态动词的语法特征,1 情态动词不能表示正在发生或已经发生的事情，只表示期待或估计某事的发生。,2 情态动词除ought 和have 外，后面只能接动词原形。,3 情态动词没有人称，数的变化，即情态动词第三人称单数不加-s。,4 情态动词没有非谓语形式，即没有不定式，分词，等形式。,情态动词的用法,情态动词,Modal Verbs,can,和,could,情态动词,用 法,例 句,can/could,1,“I dont think Mike,can,type.”“Yes,he,can,.”,2I,can,speak fluent English now,but I,couldnt,last,year.,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?,Can,we turn the air conditioner on?,In soccer,you,cant,touch the ball with your hands.,Could,you,have her call me back when she gets home,please?,I wonder if I,could,just ask you to sign this.,1As a human being,anyone,can,make a mistake.,2Im confident that a solution,can,be found.,3He,can be,very forgetful sometimes.,Can,this be an excuse for not giving them help?,This,cant,be true.,How,can,you be so crazy.,1.表示,能力,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。,表示惊异、疑心、不相信等态度，主要用在否认句、疑问句和感慨句中。,在肯定句中，表示客观可能性，常用来说明人或事物的特征译为“有时会。要表达具体某事实际发生的可能性时，不用can，需用could，may，might。,表示对现在的动作或状态进行主观的猜测，主要用在否认句和疑问句中。,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.(否认答复可用：No,Im afraid not.或者是you cant),2.表示推测时，could不是过去式，只是语气更委婉；假设是推测已发生的事或过去的情况，用can/could have done,3.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那么有更多的形式。如：,Ive always wanted to be 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/were able to来表示。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.,4 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。,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,May I come in and wait?,May I smoke here?,No,you mustnt(,或,No,youd better not.),Might I borrow your pen,I wonder if I might speak to your son.,It may rain this afternoon.,She might come to join us this afternoon.,I suppose he might have missed the train.,May you succeed.,May you live happily!,May she rest in peace.,愿她安息。,There is nothing to do,so I may as well go to bed.,You may as well tell us now,well find out sooner or later.,I suppose we might as well go home.,表示允许、许可。否认答复一般用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。,在表示请求、允许时，might比may语气更委婉些。用May I征询对方许可在文体上比较正式，在日常用语中，用Can I征询对方意见更为常见。,表示可能性的推测，通常用在肯定句和否认句中，含有“或许“大概“可能之意；用might代替may时，那么语气显得更加不肯定。,may用于祈使句表示,祝愿,惯用句式：,“may as well或might(just)as well+动词原形意为“最好，满可以，倒不如，相当于“had better.,1.A computer _ think for itself;it must be told what to do.,A.cant B.couldnt C.may not D.might not,I thought you _ like something to read,so I have brought you some books.A.mayB.mightC.couldD.must,may,might,can,could,1.They(can/might)_be away for the weekend but Im not sure.,2.You(may/might)_leave now if you wish.,3.(could/may)_you open the window a bit,please?,4.He(can/could)_be from America,judging by his accent.,5.(may/can)_you swim?,6.Listen,please.You(may not/might not)_ speak during this exam.,might,表示猜测,may,表示许可,could,表示请求,could,表示猜测,can,表示能力,may,not,表示不允许,may,might,can,could,7.They(can not/may not)_ still be out,the light is on in the house.,8.You(couldnt/might not)_ smoke on the bus.,9.With luck,tomorrow(can/could)_be a cooler day.,10.You(can/might)_ be right,but Im going back to check it.,表示许可,couldnt,could,表示猜测,can,not,表示猜测(不可能),might,表示猜测,三must和have to,情态动词,用法,例句,must,You must come to school on time.,Everybody must obey the law.,You mustnt drive so fast in the street.,We mustnt waste any more time.,1Must I come back before ten?,Yes，you must.,-No,you neednt(No,you dont have to),It must be my mother.,You must be hungry after a walk.,There must be a hole in the wall.,have to,The film is not interesting.I really must go now.,I have to go now,because my mother is in hospital.,1I had to work hard when I was your age.,2I will have to learn how to use acomputer.,3In order to take the exam,well have to finish the whole book by the end of this month.,You mustnt go there.,You dont have to go there.,表示“必须，应该之意，语气比should，ought to强烈。其否认形式mustnt表示“不准，不应该，禁止等意,在答复带有must的问句时，否认答复常用neednt或dont have to，表示“不必，而不用mustnt,表示有把握的推测，意为“一定、准是、相必，只用于肯定句中,“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那么往往强调客观需要。,must只有一种形式，即现在式与过去式都是一种形式，而have to那么涉及各种人称、时态等方面的变化形式。,两者的否认意义不同，mustnt表示“禁止，不许，dont have to表示不必。,注意：表示偏要，硬要做某事,-how old are you,madam?,-if you mu