高中英语情态动词讲解.ppt

1、Grammar:Modal verbsHow many modal verbs do you know?can couldmay mightshall shouldmust will wouldought tohave to dare (darent)need (neednt)used to表示推测表示推测不表示推测不表示推测modal verbs表示推测表示推测一定，肯定一定，肯定 must一定不，不可能一定不，不可能cant,couldnt可能肯定句可能肯定句 may,might,could否定句否定句 may might not疑问句疑问句 can,could 都可以都可以+do sth

2、.表示现在表示现在 be doing 表示正在发生的动作表示正在发生的动作 have done表示表示过去发生的动作过去发生的动作He must have a car now.must表示推测时，可以推测现在表示推测时，可以推测现在/正在发生正在发生的动作的动作/过去发生的动作。过去发生的动作。他一定有一辆车他一定有一辆车他一定在教室里做练习。他一定在教室里做练习。他一定已完成了工作他一定已完成了工作He must have finished the work.He must be doing his exercises in the classroom.一定不，不可能一定不，不可能 cant

3、 couldntHe cant be at home.He couldnt have said such a thing.他们一定不在图书馆读书。他们一定不在图书馆读书。约翰是很聪明的，他应该不会叫他儿子那约翰是很聪明的，他应该不会叫他儿子那样做。样做。They cant be reading in the libraryJohn is very clever.He cannot have told his son to do that.可能可能肯定句肯定句 could,may,might否定句否定句may might not（可能不）（可能不）疑问句疑问句 can,couldv他可能正在睡觉

4、。他可能正在睡觉。These students may/might have seen the film before.否定句否定句The boy may/might not be watching TV at home.（现在）（现在）这个男孩可能没在家看电视这个男孩可能没在家看电视He may/might be sleeping nowv疑问句疑问句 How could he have forgotten such an important thing?这么重要的事他怎么能忘这么重要的事他怎么能忘了呢？了呢？Its so late.Where can she have gone?天晚了，她

5、可能去哪儿了呢？天晚了，她可能去哪儿了呢？Can you have left the watch at home?你你会不会把表丢在家里呢？会不会把表丢在家里呢？一.一.Choose the best answers to complete the Choose the best answers to complete the following sentences:following sentences:1.I thought you_ like something to read.So I have brought you some books.A.ought B.might C.coul

6、d D.must 二二.2.That man must be Sarahs husband.-No,he_ be her husband.She is still single.A.cant B.mustnt C.may not D.ought to 3.Peter _come with us tonight,but he isnt very sure.A.must B.may C.can D.will 4.What_ it be?-It_ be a mail box,for it is moving.It_ be a car.A.can;cant;must B.can;can;must C.

7、can;mustnt;must D.must;mustnt;can 5.Look,someone is coming.Guess_.-Jack.Hes always on time.A.who can it be B.who he may C.who he can be D.who it can be 6.I saw Mary in the library yesterday.-You_ her.She is still abroad.A.mustnt see B.cant have seen C.mustnt have seen D.couldnt see 7.David,you _play

8、 with the valuable bottle,you_ break it.A.wont;cant B.mustnt;mayC.shouldnt;must D.cant;shouldnt 表示能力表示能力一表示能力一表示能力can,could,be able to can表示智力，体力方面的能力只能用表示智力，体力方面的能力只能用 现在或现在或过去时。过去时。be able to通过努力克服困难作成事情通过努力克服困难作成事情,能用能用于各种时态。于各种时态。*was/were able to:设法做成某事设法做成某事 相当于相当于 managed to do sth.succeeded

9、in doing sth.。vcan与与be able to 用法区别常与句子时态有关用法区别常与句子时态有关v 1.现在时比较现在时比较v1)表示表示”能力能力”时时,be able to 不用于第二人不用于第二人称称,vYou are able to do the work,I think.(X)改用改用canvcan与感官动词与感官动词feel,hear,see,smell,taste连用时连用时,can显得可有可无显得可有可无,因而失去了情态因而失去了情态动词的意义动词的意义,这种情况下这种情况下can不能用不能用be able to 代替代替ve.g.,We can see beau

10、tiful flowers and green trees here and there.vAnyone can see it is of no use.3)can)can与某些表示意念的动词如：与某些表示意念的动词如：understand,understand,remember,forget,hope,imagine,believe,remember,forget,hope,imagine,believe,supposesuppose等连用时，同样没有情态动词的意义，也等连用时，同样没有情态动词的意义，也不可用不可用be able tobe able to取代取代。e.g.I canI ca

11、nt believe there are so many t believe there are so many tall buildings now in my home town tall buildings now in my home town v v2.过去去时比比较was/were able to 意含意含”经过努力努力”“凭借才能凭借才能”获得的得的”能力能力”常与常与”manage to”相通相通 They were short of modern machines,but they were able to complete the project in time.二表示允许

12、vcan,could,may,might might,could 表达更客气、委婉、礼貌的请求语气。表达更客气、委婉、礼貌的请求语气。Excuse me,could you tell me the way to the bus station?Could you help me?You can go now if you like.May I smoke in the room?三表示必须三表示必须ought to/should have to must *have to 能用于各种时态能用于各种时态,且有人称和数的变且有人称和数的变化化.ought to 的否定式为的否定式为ought no

13、tto或者或者oughtnt to1.should 和和ought tov大多数情况下，含义基本相同，大多数情况下，含义基本相同，should主要主要看主观看法，看主观看法，ought to更多反映客观情况，更多反映客观情况，在谈到法律，规定，义务时使用。在谈到法律，规定，义务时使用。如：如：you should try your best to pass the entrance examanations.We ought to go and see hellen,but I think we have no time.vShould 还可以表示惊讶，出乎意料的意思还可以表示惊讶，出乎意料的

14、意思 Why should he do such a thing?2.must与与have to 的用法的用法前者侧重于主观意念前者侧重于主观意念,后者则用于表示客观条后者则用于表示客观条件或义务件或义务,译为译为”只好只好”“不得不不得不”e.g.,He must work to make his living.He has to beg for a living.Must没有过去式没有过去式,在单句中若是过去时在单句中若是过去时,须用须用had to e.g.,He begged from door to door,for he had to do so to live若在从句中若在从句中

15、,则可用则可用must来表示过去来表示过去e.g.,He said he must manage to own a new house for Easter.must用于疑问句，表示责备、抱怨的感情色彩，意思为“偏要，硬要、干嘛”；四表示虚拟should have done 本应该做（而没做）本应该做（而没做）should not have done本不应该做本不应该做 He shouldnt have said such a thing .他当时不他当时不应该说那种话。应该说那种话。We should have studied last night,but we went to the co

16、ncert instead这种句式也能用这种句式也能用ought toneed not have done没有必要做某事没有必要做某事I need not have got up so early.我本来我本来不必要那么早起床的（事实上早已起床）不必要那么早起床的（事实上早已起床）I need not have waited for the train for an hour.我本来不必要等一个小时的火车。我本来不必要等一个小时的火车。（事实上已经等了一个小时）（事实上已经等了一个小时）3.could have done它表示它表示“过去本来能够过去本来能够”实际上没能做实际上没能做。If you could have finished the task in time，you could have been promoted.如如果你当时能如期完成那任务的话，你可能已果你当时能如期完成那任务的话，你可能已提升了（实际上没有被提升）提升了（实际上没有被提升）I could have laughed to hear him talk like that.听他那样讲话，我差点笑出声来。听他