1、情态动词,2,情态动词概述,情态动词表示说话人的语气或对事物的态度，情态动词本身有词义，但不能单独作谓语，必须和原形动词一起构成谓语。情态动词没有人称和数的形式变化。,英语情态动词共有9种，即can,may,will,shall,dare.must,need,ought to,used to.有的情态动词有时态的变化。变化如下： 现在式 can may will shall dare must need ought to - 过去式 could might would should dared - - - used to,3,教学目标：情态动词用法归纳(2) 教学重点： 1.情态动词表示推测;
2、2.情态动词 + have done 结构；,4,一.情态动词表示推测的用法,情态动词可用来表示推测,语气从强到弱的顺序是：,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。,must，should，can，could, may ，might。,5,二.情态动词+have done,表示对过去所发生事情的推测或带有某种语气.1. I didnt hear the phone
3、. I must have been asleep.,must have done (过去)肯定/一定(用于肯定句中),6,2. There were already five people in the car, but they managed to take me as well.It couldnt have been a comfortable journey.,cant/couldnt have done(过去)不可能,7,3. He may not have finished the exercises, Im afraid. 4. You could have done bet
4、ter, but you didnt try your best.,may/might have done(过去) 或许/可能做 (用于肯定或否定句中),could have done (过去) 本能够做 (用于肯定或否定句中,带有责备、劝告之意),8,5. When we got to the cinema, the film hadnt started, so we neednt have worried.Mary didnt turn up last night, did she?No, she didnt need to come. We had changed our plan.,n
5、eednt have done (过去)本来不必做,(没有必要做而实际上也没做).,9,6.She shouldnt have taken away my tape, for I wanted to use it.,should /ought to have done (过去)本应该做(而实际上未做),用于否定句 时则表示过去不该做的事反而做了 (带有后悔、埋怨或责备的语气）。,10,注意：,cant -不可能 mustnt -禁止，不允许 mustnt have done-（不存在）,11,(06陕西）As you worked late yesterday, you _ have come
6、 this morning.B. may notC. cant D. mustnt,A,A. neednt,12,(04全国) Mr. White_ at 8:30 for the meeting, but he didnt show up.B. should arriveC. should had arrived D. should be arriving (04福建) Ill tell Marry about her new job tomorrow.You _ her last week.A. ought to tell B. could have toldC. must tell,A.
7、 should have arrived,D. should have told,A,D,13,(05福建)Catherine, I have cleaned the room for you.Thanks. You _ it. I could manage it myself.A. neednt do C. mustnt do D. shouldnt have done,B. neednt have done,B,14,(NMET 05) He _ have completed his work; otherwise, he wouldnt be enjoying himself by th
8、e seaside.A. should C. wouldnt D. cant,B. must,B,15,(00 上海)My sister met him at the Grand Theatre yesterday, so he _ your lecture.B. neednt have attendedC. mustnt have attendedD. shouldnt have attended,A. couldnt have attended,A,16,Must 必须(04 上海)Children under 12 years of age in that country must be
9、 under adult supervision when in a public library.,三.情态动词基本用法,17,Can/Could 用在否定句、疑问句、感叹句中常表推测、惊讶、怀疑、不相信的语气：1） Who can it be? It cant be him. He has gone to Xian.2）How can you be so careless?What can he possibly mean?,18,(03上海)How _ you say that you really understand the whole story if you have cover
10、ed only part of the article.B. must C. need D. may,A. can,A,19,(04全国卷II)You _ be tired youve only been working for an hour.A. must not B. wontD. may not (06全国卷I)There is no light on They _ at home.B. mustntC. neednt D. shouldnt,C. cant,A. cant,C,A,20,(06福建）If it werent for the fact that she _ sing,
11、I would invite her to the party.A. couldnt B. shouldntD. might not (06四川）Is Jack on duty today?It _ be him. Its his turn tomorrow.A. mustnt B. wont D. neednt,C. cant,C. cant,21,Can 在肯定句中使用表示1)有时候的可能性: The World Wide Web is sometimes jokingly called the World Wide Wait because it can be slow.(05浙江).H
12、e can be friendly at times.,22,2) 理论上的可能性,并不涉及具体某事是否真会发生,主要是说明人和事物的特征: 1.Even expert drivers can make mistakes. 2.(2003) A left-luggage office is a place where bags can be left for a short time, especially at a railway station. 3. Training by yourself in a gym can be highly dangerous. 4. Bird Flu ca
13、n be dangerous.,23,Making choices _ difficult, especially when there is no one to turn to for advice. A. might B. should D. must,C. can,C,24,但是在表达具体某事实际发生的可能性时不可用can, 用may/might/could.1) He may /might / could be in the library.2)A snowstorm can be exciting, but too much snow can cause trouble. 3) Th
14、is storm may/might/could last several days.,25,Could 表可能性,语气较弱; 表请求,较委婉。Could you lend me some money?Yes , I can.(98 上海)“ Could I call you by your first name?”“ Yes, you _.A. will B. could D. might,C. may,C,26,was able to 和 could 的区别 The fire spread through the hotel very quickly, but every one was
15、able to get out. （强调经过一番努力后成功做到某事. He didnt agree with me at first, but I was able to persuade him.She could sing when she was young. (一般能力),27,Can的惯用语1.cant (help/choose) but + v (不得不）I cant help but admire your bravery.2. cant help doing.区别 /cant help (to) do.3. cant help it.“ Why are you crying?”
16、 “ I just cant help it.4. cant/ couldnt 与too, enough连用.You cant be too careful. 再也不过分 I cant thank you too much.,28,Will/Would意志、愿望和决心。1)I will never do that again.2)If you will wait over for a long time, Mr. Smith, I will tell our manager youve arrived. 习惯、倾向，多用于第三人称。He will sit there hour after ho
17、ur doing nothing.Boys will be boys.,29,坚决拒绝。I wont listen to your nonsense.The dog wouldnt stop barking. 表临时的决定“ You forgot to post my letter.”“ Sorry, I will post it .,30,Used to do /would do1) She isnt what she used to be.( 表对比)2) We would sit in the yard every Sunday and listen to his story.( 表过去
18、习惯性动作),31,May/Might 表不确定的可能性.1)(NMET00) “ Are you coming to Jeffs party?“Im not sure. I might go to the concert instead.2)Peter may come with us, but he isnt very sure yet.,32,用于祈使句,表示祝愿.May you return safe and sound.May you be happy!may/might as well do 不妨,不如Now that youve got so far with the work, you might finish it as well.,33,dare and need,
