1、can 和和 could 1.1.can/could can/could 表示能力，只用于现在式和表示能力，只用于现在式和过去式过去式 (could)(could)。be able tobe able to2 2.can 表示客观可能性表示客观可能性.Anybody can make mistakes.It can be cold in winter in the south.3.3.表示许可表示许可.You may/can come in.4.4.用在否定句或疑问句中用在否定句或疑问句中,表猜测表猜测,怀疑怀疑,惊讶惊讶That cant be Tom.He went to London t
2、wo weeks ago.The fire spread through the The fire spread through the hotel very quickly but hotel very quickly but everyone _ get out.everyone _ get out.A had to B would A had to B would C was able to D could C was able to D couldC He could swim across the English Channel.But he didnt feel like it t
3、hat day.(能力）能力）Yesterday I was able to get home before the heavy rain.Be able to do sth=manage to do sth =succeed in doing sth1.表示允许或请求表示允许或请求 can may/can I help you?2.没有把握的推测。没有把握的推测。She may come tomorrow.She may not(可能不）可能不）go to the party tonight.3.放在句首放在句首,表示祝愿。表示祝愿。May God bless you!might 表示推测时
4、表示推测时,不表示时态不表示时态,只是可能只是可能 性比性比may 小。小。They might be having a meeting,but Im not sure.may 和和 might-Are you coming to Jeffs-Are you coming to Jeffs party?party?-Im not sure.I _go to-Im not sure.I _go to the concert instead.the concert instead.A must B would A must B would C should D might C should D m
5、ightD -Is John coming by train?-Is John coming by train?-He should,but he_not.He -He should,but he_not.He likes driving his car.likes driving his car.A must B can C need D mayA must B can C need D mayD Peter _come with us tonight,but he isnt very sure yet.A.mustB.may C.can D.will答案B.表可能性只能用may.此句意可从
6、后半句推出。Im sure he_have the Im sure he_have the computer sooner or computer sooner or later.later.A shall B can A shall B can C must D would C must D wouldC have to和must“必须”1.have to表示由于客观因素不得不做 must表示说话人的主观意志,看法1.My brother was very ill,so I had to call the doctor in the middle of the night.2.He said
7、 that they must work hard.2.have to有人称、数、时态的变化，而must只有一种形式。He had to look after his sister yesterday.3.否定结构中 dont have to表示“不必”mustnt表示“禁止”You dont have to tell him about it.你没必要把此事告诉他。You mustnt tell him about it.你一定不要把这件事告诉他。4.Must I return the book today?-Yes,you must.-No,you neednt./No,you dont
8、have to.Need I call her again?-Yes,you _.-No,you _.must neednt dont have toMay I use your bicycle?-Yes,you _.-No,you _.maycant-May I use your-May I use your motorbike?motorbike?-No,you _.-No,you _.A cant B shouldnt A cant B shouldnt C neednt D mustntC neednt D mustntA May I leave now?-Yes,you may.-N
9、o,youmustnt.We must go now,_?-Must we go now?-Yes,you _.-No,you _.neednt you must neednt dont have to1.will 在疑问句中表示请求和建在疑问句中表示请求和建议议.would 比比will 更婉转更婉转,礼貌礼貌 Will you come to my office?2.表示愿意去做某事或决心做某事表示愿意去做某事或决心做某事.I will marry you.If you will come to the party,we will be very happy.作为情态动词作为情态动词wil
10、l will 可以用于条件状语从句可以用于条件状语从句will 和和wouldwould和和used to1）used to表示过去与现在或过去某时与后表示过去与现在或过去某时与后来的情况有不同，而来的情况有不同，而would只表过去的情况只表过去的情况(过去往往过去往往)。People used to think that the earth was flat.She would go out for a walk in the morning when she was in the country.2）used to可表示过去习惯性的动作和经常可表示过去习惯性的动作和经常的状态，的状态，w
11、ould只表示过去习惯的动作。只表示过去习惯的动作。He used to/would smoke while writing.She used to be fat.shall1)在疑问句中在疑问句中shall用于一用于一,三人称三人称,表示表示征求对方的意见或指示征求对方的意见或指示Shall he come to see you?What shall I do to help you?2)在陈述句中在陈述句中shall 用于二用于二,三人称三人称,表示表示告戒告戒,警告警告,命令命令,决心决心,允诺等意图允诺等意图.He shall go with us.I think you shall
12、do it.1.Shall I carry your luggage?2.Shall he come to see you?1.You shall do as I say.2.Nobody shall say a word.3.You shall fall behind in your exam if you keep playing.1.You shall have a nice present for your birthday.2.He shall have the book when I finished reading it.1.-The room is so 1.-The room
13、 is so dirty._we clean it?dirty._we clean it?A.Will B.Shall A.Will B.Shall C.Would D.Do C.Would D.DoB 2.-Excuse me,but I want to 2.-Excuse me,but I want to use your computer to type a use your computer to type a report.report.-You _have my -You _have my computer if you dont take computer if you dont
14、 take care of it.care of it.A shant B might not A shant B might not C neednt D shouldnt C neednt D shouldntA should1).should(主观主观)和和ought to(客观客观)都表示劝告,建议或有责任,义务去做某事为“应该,必须”的意思，可用于各种人称。You should do as I told you.2).Should/ought to have done表示某事在过去本应该做而实际未做;shouldnt/oughtnt have done 本不应该本不应该做而实际却做了
15、做而实际却做了.(责备)Youshouldhavecomehereearlier.Youshouldnthavebeenthere.1.Students should respect teachers.2.He suggested that we should act at once.3.The boys shouldnt be playing football.They should be at school.4.You shouldnt have entered the teachers office without permission.5.He should be 20 years.6
16、.It should be fine tomorrow.need和和dare 1)作为情态动词时，两者都主作为情态动词时，两者都主要用于疑问句、否定句和条件要用于疑问句、否定句和条件句。句。2)need 作实义动词时后面的作实义动词时后面的不定式必须带不定式必须带to，而，而dare作实作实义动词用时义动词用时,后面的后面的to 时常可时常可以被省略。以被省略。-Dare you go there alone?-Yes,I _.-No,I _.You dare go there alone,_?You dare to go there alone,_?dare dare not darent
17、you dont you3)need 否定结构否定结构neednt=dont have to没有必要没有必要,不必不必.4)need/neednt have done表示本有必要做某事，而实际表示本有必要做某事，而实际未做未做或本没必要做，而实际却做或本没必要做，而实际却做了了We _ to school on We _ to school on Sundays.Sundays.A neednt going A neednt going B neednt to go B neednt to go C dont need go C dont need go D neednt goD neednt
18、 goD 情态动词 have donemust have done对过去某事的肯定猜测对过去某事的肯定猜测想必，一定，准是想必，一定，准是cant/couldnt have done对过去某事的否定性猜测对过去某事的否定性猜测想必不可能，一定不想必不可能，一定不may/might have done对过去某事的可能性猜测对过去某事的可能性猜测可能已经可能已经should/ought to have done 过去应该做而实际未做过去应该做而实际未做本应该本应该(责备责备,语气较强语气较强)could have done 本来能做的事实际却未做到本来能做的事实际却未做到(遗憾遗憾,惋惜惋惜)情态
19、动词情态动词+have+过去分词过去分词 1.must have+done sth对过去时间里可能发生的事情的推测，对过去时间里可能发生的事情的推测，语气较强，具有语气较强，具有肯定肯定，谅必谅必的意的意思。思。Linda has gone to work,but her bicycle is still here.She must have gone by bus.2 ought to should had better 本应该做某事，而事实上并没有做。否定句表示“本不该做某事而做了”。You ought to/should have been more careful in this ex
20、periment.He ought not to have thrown the old clothes away.You had better have come earlier.have done sth3.neednt have done sth本没必要做某事本没必要做某事I dressed very warmly for the trip,but I neednt have done so.The weather was hot.1._he_a famous doctor at that time?He was so young then.A Can;be B Must;be C Ca
21、n;have been D Must;have beenC can have done could have done 用于表示对用于表示对过去过去发生发生的事进行猜测的事进行猜测,can 只能用于疑问句只能用于疑问句,否定句否定句,其他情况用其他情况用could.could have done还课用来表示还课用来表示“本来能做而没本来能做而没做做,有责怪的意思有责怪的意思”例 (1)-Where can she have gone?-She can not have gone to the church.-She could have gone swimming.(2)-Why didnt
22、you come back?You could have saved her.2.My English-Chinese 2.My English-Chinese dictionary has dictionary has disappeared.Who_ disappeared.Who_ have taken it?have taken it?A should B must A should B must C could D would C could D wouldC 3.-Will you stay for lunch?3.-Will you stay for lunch?-Sorry,_
23、.My brother-Sorry,_.My brother is coming to see me.is coming to see me.A I mustnt B I couldntA I mustnt B I couldntC I neednt D I wontC I neednt D I wontB 4.I was really anxious 4.I was really anxious about you.You_home about you.You_home without a word.without a word.A mustnt leave A mustnt leave B
24、 shouldnt have leftB shouldnt have leftC couldnt have left C couldnt have left D neednt leaveD neednt leaveB 5.-I stayed at a hotel in 5.-I stayed at a hotel in New York.New York.-Oh,did you?You_with-Oh,did you?You_with Barbara.Barbara.A could have stayedA could have stayedB could stayB could stayC
25、would stay C would stay D must have stayedD must have stayedA 6.The light is on.Mr Wang 6.The light is on.Mr Wang _up._up.A will have got A will have got B must be getting B must be getting C must be get C must be get D must getD must getB 1.You must be hungry now,_?2.He must be listening to the mus
26、ic,_?3.She didnt do her homework.She cant have studied last night,_?4.You must have finished your homework,_?arent youisnt hedid she havent you1.I must go now,_?2.He must be angry,_?3.He must be angry just now,_?4.He must have gone abroad,_?5.He must have gone abroad last month,_?如果后是助动词如果后是助动词be ha
27、ve 那么就根据助动词的那么就根据助动词的正确形式填空；如果后是实意动词则根据情态动正确形式填空；如果后是实意动词则根据情态动词进行填空；如果有时间状语则根据时间状语进词进行填空；如果有时间状语则根据时间状语进行变化行变化 neednt you isnt he wasnt he hasnt hedidnt he表示否定的情态动词的用法表示否定的情态动词的用法:mustnt 不准不准,禁止禁止 neednt 没必要没必要(=dont have to)cant 不能不能;不可能不可能may not 不可以不可以;可能不可能不shouldnt 不应该不应该(=ought not to)Exercis
28、es1.Could I borrow your dictionary?Yes,of course,you_.A.mightB.will C.can D.should 答案C.could表示委婉的语气，并不为时态。答语中of course，表示肯定的语气，允许某人做某事时，用can和may来表达，不能用could或might。2.Shall I tell John about it?No,you _.Ive told him already.A.needntB.wouldnt C.mustntD.shouldnt答案A。neednt 不必，不用。wouldnt 将不,不会的。mustnt 禁止、
29、不能。shouldnt不应该。本题为不需要，不必的意思，应用neednt。3.Dont forget to come to my birthday party tomorrow._.A.I dont B.I wont C.I cant D.I havent 答案B.will既可当作情态动词，表请求、建议、也可作为实义动词表意愿、意志、决心，本题表示决心，选B。4.Tom ought not to _ me your secret,but he meant no harm.A.have toldB.tell C.be tellingD.having told答案A。由于后句为过去时，告诉秘密的动
30、作又发生在其前因，此地应用过去完成时，但它在情态动词 ought to 后，所以用have。5.The poor girl has neither shoes or skirt.Thats why she _ stay at home.A.must B.has to C.should D.ought to6.Johnny,you _ play with the knife,you _ hurt yourself.A.wont;cantB.mustnt,may C.shouldnt;must D.cant,shouldnt7.Jack_ yet,otherwise he would have t
31、elephoned me.A.mustnt have arrived B.shouldnt have arrived C.cant have arrived D.need not have arrived8.There were already 5 people in the car but they managed to take me as well.It _ a comfortable journey.A.cant be B.shouldnt be C.mustnt have been D.couldnt have been9.Sorry Im late.I_ have turned o
32、ff the alarm clock and gone back to sleep again.A.might B.should C.can D.will10.Are you coming to Jeffs Party?Im not sure.I _ go to the concert instead.A.must B.would C.should D.might11.My sister met him at the Grand Theatre yesterday afternoon,so he _ your lecture.A.couldnt have attended B.neednt have attended C.mustnt have attended D.shouldnt have attended
