1、情态动词的语法特征情态动词的语法特征2)情态动词不能单独做谓语情态动词不能单独做谓语,后面只能接动词后面只能接动词原形，原形，ought to和和have to除外，除外，。3)情态动词没有人称情态动词没有人称,数的变化数的变化,但有些情态但有些情态动词动词,如如can、will、have to、may等有过去式。等有过去式。1）情态动词表说话人的某种感情或语气，对）情态动词表说话人的某种感情或语气，对某一动作或状态的某种态度。某一动作或状态的某种态度。1)Some of us can use the computer now,but we couldnt last year.2)Can sh
2、e be in the computer center?3)I though what he said could not be true.4)Can/Could I use your dictionary?5)Could you lend me a hand?1.1.表能力表能力,意为意为“能，能够能，能够”，cancan指现在，指现在，couldcould指过去。指过去。3.表示表示“请求请求”“允许允许”(表请求时，口语中常用表请求时，口语中常用 could 代替代替 can 使语气更委婉，回答时用使语气更委婉，回答时用can)2.表示推测，意为表示推测，意为“可能可能”“”“或许或许”
3、，用于疑问句或，用于疑问句或否定句，否定句，cant和和couldnt意为意为“不可能不可能”。1.can 与与could4.can 用于疑问句或否定句中时，表惊异、用于疑问句或否定句中时，表惊异、不相信等，意思是不相信等，意思是“可能、能够可能、能够”。6)How can you believe such a liar like him?5.cant/couldnt have done 表示对过去情况的否定推表示对过去情况的否定推测测,意为意为“过去不可能做过某事过去不可能做过某事”7)Susan cant have written a report like this.8)She cant
4、 have gone to school,it is Sunday.6.can/could have done表对过去的推测，意为表对过去的推测，意为“过去可过去可能做了某事能做了某事”。could have done还可以表示还可以表示对过去能做对过去能做而未做的事情感到惋惜，意为而未做的事情感到惋惜，意为“本能够做某事可事实上本能够做某事可事实上未做未做”9）Its a pity.Your class could have got the first prize.10）Where can Mary have gone?can表示表示“能够能够”时与短语时与短语be able to同义，同义
5、，但但can只用于一般现在时或过去时，而后只用于一般现在时或过去时，而后者可用于各种时态。另外，者可用于各种时态。另外，can表示个人表示个人有某种能力，而有某种能力，而be able to表示某人通过努表示某人通过努力、克服困难做成某事，相当于力、克服困难做成某事，相当于succeed in doing sth.；can/be able to Michael _ be a policeman,for hes much too short.A.neednt B.cant C.should D.may2.Mr.Bush is on time for everything.How _ it be
6、that he was late for the opening ceremony?A.can B.should C.may D.must3.-I stayed at a hotel while in New York.-Oh,did you?You _ with Barbara.A.could have stayed B.could stay C.would stay D.must have stayed My sister met him at the Grand Theater yesterday afternoon,so he _ your lecture.A.couldnt have
7、 attended B.neednt have attended C.mustnt have attended D.shouldnt have attendedBAAA5.Theres someone outside.Who _it be?A.can B.need C.may D.must6.-Is Jack on duty today?-It _ be him.Its his turn tomorrow.A.mustnt B.wont C.cant D.neednt7.It is usually warm in my hometown,but it _be rather cold somet
8、imes.A.can B.need C.dare D.must8.The fire spread through the hotel very quickly,but everyone _ get away.A.were able to B.would C.was able to D.couldACAC2.may 与与might1.表示表示“许可许可”或或“请求请求”，有，有“可以可以”的意思，口语中的意思，口语中 常用常用 might 代代 may,表示委婉语气。表示委婉语气。否定回答时用否定回答时用“must not”表表“禁止，阻止禁止，阻止”，不用不用“may not”.“may no
9、t”表示表示“可能不可能不”。Eg:1)-May I watch TV after supper?-Yes,you may./No,you mustnt.2)Today is Sunday.She may not in her office now.2.表示可能性。表示可能性。意为意为“或许，可能或许，可能”might 比比 may 可能性小。可能性小。Eg:1)The girl might be sleeping this time of day.2)They may be in the library now.4.may/might as well+动词原形动词原形“还是还是的好的好”“不
10、妨干某事不妨干某事”Eg:You may as well go and have a look.3.may/might have done 表示对过去发生过的事情的推测，表示对过去发生过的事情的推测，意为意为“可能已经做过某事可能已经做过某事”Eg:I cant find my sunglasses.I may/might have left them in your office.1.Sorry Im late.I _ have turned off the alarm clock and gone back to sleep again.A.might B.shouldC.can D.wi
11、ll2.Peter _ come with us tonight,but he isnt very sure yet.A.must B.may C.can D.willAB3.will 与与would 1.用于第二人称的疑问句中，表用于第二人称的疑问句中，表“请求、建议请求、建议”等，用等，用 would 比用比用will 委婉，客气些委婉，客气些Eg:1)Will you lend me your book?2)Would you like a cup of tea?2.用于表示意志或意愿，意为用于表示意志或意愿，意为“会，愿意会，愿意”。will 指现在，而指现在，而 would 指指 过
12、去。过去。用于否定句中，表示用于否定句中，表示“不会、不肯、不乐意不会、不肯、不乐意”。Eg:1)I wont do that again.2)They said that they would help us.3)No matter what I said,he wont listen to me.3.表示习惯性动作。表示习惯性动作。译作译作“总是、惯于总是、惯于”，will 指现在指现在常常，常常，would 指过去常常。指过去常常。Eg:1)This man is strange.He will sit for hours without saying anything.2)Mary w
13、ill keep asking some silly questions.3)Every evening,she would sit by window,deep in thought.4)We would sit around Grandpa after supper,listening to his stories.If you _ wait here for another 5 minutes,our manager will come back.A.should B.will C.need D.must2.When he was there,he_ go to that coffee
14、shop at the corner after work every day.A.would B.should C.had better D.might BA4.should与与ought to1.ought to比比should语气更重。两者都用于表劝告、建议。语气更重。两者都用于表劝告、建议。意为意为”应该、应当应该、应当”。但在疑问句中常用但在疑问句中常用should。ought to的否定式为的否定式为oughtnt to或或ought not to。Eg:I should help her because she is in trouble.You ought to take ca
15、re of the baby.Should I open the window?What should we do next?2.两者都可表示推测，表示很大的可能性。两者都可表示推测，表示很大的可能性。意为意为“可可能、按理该能、按理该”Eg:1)Its 7 oclock,he should be at home.2)They should have arrived by now.3.ought to/should have done 本应该干某事可事实未干本应该干某事可事实未干 oughtnt to/shouldnt have done本不该干某事可事实本不该干某事可事实 却干了却干了Eg:
16、You should have invited me to the party yesterday.You are right.I Should have thought of that.You shouldnt have eaten all the cakes in one day.4.Should可以用来表示说话人的惊奇等情感，意为可以用来表示说话人的惊奇等情感，意为“竟然，居然竟然，居然”Eg:1)Its surprising that Mary should love such a person.2)Its unbelievable that the boy should sing s
17、uch a beautiful song.1.You cant imagine that a well-behaved gentleman _ be so rude to a lady.A.can B.should C.may D.must2.-When can I come for the photos?I need them tomorrow afternoon.-They _ be ready by 12:00 A.can B.should C.might D.need3.We _ last night,but we went to the concert instead.A.must
18、have studied B.might study C.ought to have studied D.would studyBBc5.shall1.Shall用于第一、三人称的疑问句中，表示说话人征用于第一、三人称的疑问句中，表示说话人征求对方的意见或请求。求对方的意见或请求。Eg:1)Shall we begin our discussion?2)Shall I change the clothes for the child?3)Shall Tom go there with me tomorrow?4)Henry is waiting outside.Shall he come in
19、?2.Shall用于二、三人称的陈述句，表示说话人用于二、三人称的陈述句，表示说话人 的允诺、警告、命令、威胁等语气。的允诺、警告、命令、威胁等语气。Eg:1)You shall get an answer from me tomorrow.2)He shall be punished.3)You shall go with me.4)Tell Jerry that he shall get a gift if he behaves well.Chairman Zhang,many people want to see you._they wait here or outside?A.shal
20、l B.can C.should D.may2.You _use my bike if you can return it to me before Ileave here.A.should B.shall C.need D.must3.You _be punished if you break the rule.A.shall B.should C.need D.mustABAmust/haveto/need1.must用于一般问句中用于一般问句中,肯定回答用肯定回答用must,否定回答用否定回答用 neednt或或dont have to，意，意为为“不必不必”。mustnt表示表示“禁止
21、，不允许禁止，不允许”MustIfinishallhomeworkatatime?Yes,youmust.No,youneednt/donthaveto.I dont like this TV set.We must buy a new one.Mother was out,so I had to look after the shop.2.表示表示“必须必须”这个意思时，这个意思时，must 和和have to 稍有区别。稍有区别。must着重说明主观着重说明主观看法，看法，have to 强调客观需要。另外，强调客观需要。另外，have to 能用于更多时态。能用于更多时态。Youmust
22、bethenewteacher.Hemustbejoking.Thereisnobodyhere.Theymusthaveallgonehome.3.must表示对某人某事的肯定猜测表示对某人某事的肯定猜测,作作“准是准是”,“一定一定”,用于用于肯定句肯定句中。对中。对过去发生的事情作肯定判断用过去发生的事情作肯定判断用must have done，意为过去一定已经做过某事。，意为过去一定已经做过某事。Whymustyoualwaysinterruptme?Ifyoumustsmoke,doitoutside,pleaseWhymustitrainonSunday?4.must表示与说话人愿
23、望相反，翻译成表示与说话人愿望相反，翻译成“偏要，偏要，硬要，非要硬要，非要”5.注意对注意对need问句的回答问句的回答:-Need I finish the work today?-Yes,_.No,_.No,_.you mustyou needntyou dont have to-Must we do it now?-No,you _.neednt(dont have to)【考例考例】The boss has given everyone a special holiday,so we _ go to work tomorrow.(上海上海 2019春春)A.cant B.mustnt
24、C.neednt D.shouldnt【点拨点拨】考查情态动词。根据题意考查情态动词。根据题意,可知可知这里表示这里表示“没有必要没有必要”,故只能选故只能选C项。项。【考例考例】What do you think we can do for our aged parents?You _ do anything except to be with them and be yourself.A.dont have to B.oughtnt toC.mustnt D.cant【点拨点拨】根据题意根据题意“除了和他们呆在一除了和他们呆在一起做你自己外起做你自己外,没有必要做任何事情。没有必要做任何事
25、情。”可知这里选择可知这里选择dont have to表示表示“不必不必”。故选故选A项。项。【考例考例】-Jane has just come back from China and she looks happy.-She _ her trip very much.must enjoy B.must have enjoyedC.may enjoy D should have enjoyed【考例考例】You _ return the book now,you can keep it until next week if you like.cant B.mustntC.neednt D.ma
26、y not【考例考例】Where is Dad,Mary?He _ the flowers in the garden.must water B.must be wateringC.Must have watered D.watered【考例考例】-Whats the matter with the man hanging his head there?-Well.If you _know,he was caught stealing my bike.must B.may C.can D.shall情态动词表推测用法小结情态动词表推测用法小结情态动词情态动词对现在或将来对现在或将来情况的推测情
27、况的推测对现在或将来对现在或将来正在进行的推正在进行的推测测对过去情况的对过去情况的推测推测肯定推测肯定推测 mustmust+vmust+be doingmust+have done可能推测可能推测may/mightmay/might+v may/might+be doingmay/might+have done否定推测否定推测cant/couldntcant/couldnt+vcant/couldnt+be doingcant/couldnt+have done疑问推测疑问推测can/couldcan/could+vcan/could+be doingcan/could+have done
28、 情态动词情态动词+have done这是历年高考热点之一，这是历年高考热点之一，可表示可表示“推测、责备、怀疑推测、责备、怀疑”等多种意义。等多种意义。一、表示对过去事情的推测或估计一、表示对过去事情的推测或估计1.must have done “过去肯定已经做了某事过去肯定已经做了某事”eg:The ground is rather wet,so it must have rained last night.2.may/might have done “可能可能/大概已经做了某事大概已经做了某事”eg:Tom may have gone to shanghai,but I still no
29、t sure about it.3.cant/couldnt have done“不可能已经做了某事不可能已经做了某事”eg:The ground is very dry,so it cant have rained last night注：在疑问句中注：在疑问句中 can/could 表示对过去情况的疑问性表示对过去情况的疑问性 推测，推测，“可能已经可能已经了吗？了吗？”eg:Someone must have broken into our bedroom,Who could have done it?二、表示对过去所发生事情的遗憾或责备二、表示对过去所发生事情的遗憾或责备1.shoul
30、d/ought to have done“过去本应该做而没做过去本应该做而没做”eg:I really regretted wasting the hours when I should have studied hard,but it was too late.2.shouldnt/oughtnt to have done “过去本不应该做的事却做了过去本不应该做的事却做了”eg:Im very sorry for the words I shouldnt have said to you at that moment.3.could/might have done“本来能够做的事却没做本来
31、能够做的事却没做”eg:He could have worked out the problem.4.neednt have done“原本不必做的事却做了原本不必做的事却做了”eg:Your home is not far from your school,so you neednt have left in such a hurry.5.Would like to have done “本打算做某事但没做成本打算做某事但没做成”eg:I would like to have come to visit you,but I had to look after my sick mother at home.
