情態(tài)動詞與虛擬語氣

1、2016年7月27日一、情態(tài)動詞的用法一、情態(tài)動詞的用法（一）can的用法can：有能力、可以做、有時會、可能、允許1、表示體力或者智力上的能力（能做某事）He can speak English.2、表示可能（表猜測，多用于否定或疑問句）Who can it be?It cant be true.3、表示“有時會”，即不經(jīng)常發(fā)生或者偶然發(fā)生的情況。Chengdu can be very hot in summer.Boys can be very naughty.4、表示“允許”（與may同義，多用于口語）You may use my computer.You cant make so mu

2、ch noise.5、表示“驚訝”（常用于疑問句、否定句）How can you believe in such a person?How can that be true?6、can的習(xí)慣用法can but 只好cant help but do 或cant help but doingcannottoo 再也不過分You cannot be too careful to across the road.You can never read English too much.（二）could的用法could作為can的過去式，可以表示能力、可以做、有時會、可能、允許等意義。也可以代替can說明

3、現(xiàn)在的情況，表示語氣的委婉。1、表示過去的能力過去的能力When she was five years old,she could ride a bike.2、表示可能性可以表示過去的可能性，也可以表示現(xiàn)在的可能性，但是在程度上比can要弱一些。He said the news could be true.（過去的）Someone is knocking at the door.Who could it be?（現(xiàn)在的）3、有禮貌的請求或者建議 委婉地提出想法、請求或者建議。 需要注意的是，在回答時，需要can,不能用couldCould you please show me the way?

4、Yes,I can.I could do it right now if you like.4、表示虛擬語氣I wish I could be 10 years younger.反饋訓(xùn)練反饋訓(xùn)練反饋訓(xùn)練You_be tired;youve only been working for an hour.A. must not B.wont C.cant D.may not 猜測The college entrance exam _be easy sometimes.So take it easy when you are well prepared.A.may B.shall C.canD.cou

5、ld有時會The World Wide Web is sometimes jokingly called the World Wide Wait because it_be very slow.A.should B.mustC.will D.can有時會Could I have a word with you?Of course you_A.may B.can C.could D.should_the incident have happened last term?No.At the very beginning of this term as much as I could remembe

6、r.A.shouldB.might C.MustD.Could 表示可能性，此處為過去的可能性Im going to Europe on vacation together with John if I_find the money.A. can B.mightC.would D.need能力（三）may的用法may主要用來表示許可、可能、祝愿等。1、征求對方的意見此時，做肯定回答時用may或can，做否定回答時用mustntMay I take a look of your scores?Yes,you may/can.No,you mustnt.2、表示推測表示推測時，一般用于肯定句和否定

7、句中，疑問句中應(yīng)用can表示推測。He may come here soon.He may not come here soon.3、表示祝愿May you happy！May you success!4、用于目的狀語從句中Open the window so that the fresh air may come through.（四）might的用法might為may的過去式，也可以代替may說明現(xiàn)在的情況，口氣比may更委婉些。1、表示許可He asked me if he might go home.2、表示可能性可以指過去的、現(xiàn)在的可能性。指現(xiàn)在的可能性時比may程度弱。He tol

8、d me he might fail in the exam.（過去）He might come tomorrow,but I am not sure.（現(xiàn)在的可能性）2012年四川卷I got close enough to hear them speaking chinese,and I said “Nihao”just as I might do in China.情態(tài)動詞間的區(qū)別情態(tài)動詞間的區(qū)別1、can與may表示可能性時的區(qū)別can表示理論上的，一般性的可能性may表示實際發(fā)生的可能性I can take a bus to school,but I may walk to.It c

9、an be very hot here at this time of year,but it may get very cold tomorrow.2、may not與cant語意的區(qū)別may not表示“可能不”，語氣不確定的推測cant表示“不可能”，語氣確定的推測You may be right or may not be right.It cant be postman at the door.Its only 6 am.反饋練習(xí)反饋練習(xí)用適當?shù)那閼B(tài)動詞填空1.I_(not)find the way to the hospital._you show me the way?2.The

10、 cloud is lifting, so it _(not)be a rainy day tomorrow.3.May I have a look at your photo? Yes, you _.4._you both be happy.cant May/Could cant can May（五）must的用法1、表示“必須、一定要” 否定形式：mustnt“一定不要、絕對不可以”You must be here by 10 am.You mustnt talk like that.2、表示推測此時，只能用于肯定句中，常指有根據(jù)的，比較有把握的推測。must后面接完成時表示對已經(jīng)發(fā)生的事

11、情的推測He must know the answer,because he is smart.It must have rained last night,the ground is wet.3、表示偏要、硬要After I give her advice,she must go and do the opposite.含含must的疑問句的回答方式的疑問句的回答方式Must I hand my homework?Yes, you must.No,you neednt/dont have to.must表對過去的推測時表對過去的推測時 反意疑問句如何構(gòu)成？1、通常情況下，反意疑問部分用hav

12、ent或者didnt,但在句中有明確的過去時間狀語時一般用didnt.You must have left your key at home,havent you?/didnt you?It must have rained last night,didnt it?（六）shall 的用法1、表示征求對方意見Shall we use your bike for a while?2、表示許諾、命令、警告、規(guī)定、決心“What you want, you shall have it.”said Fairy.They hope to destroy us one by one, they shall

13、 fail.The day when you will succeed shall come.Every students shall wear uniform at school.（七）should/ought to的用法should表示義務(wù)和推測=ought to 但ought to語氣比should更強，強調(diào)有責(zé)任、有義務(wù)或按道理應(yīng)該如何?？谡Z多用should1、表示義務(wù)、責(zé)任、勸告、建議 “應(yīng)該、應(yīng)當”You should be more careful next time.You shouldnt let the secret out.2、表示推測根據(jù)一定的依據(jù)或者常規(guī)進行的推測“按

14、理說”“照理應(yīng)該”The report is written after careful investigation, so it should be reliable.If he started at seven, he ought to be here now.3、表示“本該”（含有責(zé)備意味）（1）should/ought to have done本該做，而未做（2）shouldnt/oughtnt to have done本不應(yīng)該做，而做了You shouldnt do that.You should water it more often.4、表示“竟然、居然”多用于表示驚奇、遺憾的t

15、hat從句You cant imagine that a well-behaved gentleman should be so rude to a lady.It is a pity that she should have lost all her money.反饋訓(xùn)練反饋訓(xùn)練Must I hand my homework now?No, you _.You may give it to me tomorrow.A.neednt B.mustt C.cant D.may notTom ought not to _me your secret,but he meant no harm.A.h

16、ave told B.tell C.be tellingD.having told shouldnt/oughtnt to have done本不應(yīng)該做，而做了I was really anxious about you.You_home without a word.A.mustnt leaveB.shouldnt have leftC.couldnt have leftD.neednt have leftshouldnt/oughtnt to have done本不應(yīng)該做，而做了_you interruput now?Cant you see Im on the phone?Sorry s

17、ir,but its urgent.A.Can B.Should C.MustD.Would偏要、硬要Will you read me a story?OK。You_have one if you go to bed as soon as possible.A.might B.mustC.could D.shall允諾Shall I inform him of the change of the schedule right now?I am afraid you_,in case he comes late for the meeting.A.will B.mustC.may D.can （

18、八）will/would 的用法1、表示意愿、決心（用于各個人稱）I will help you if you are in trouble.Please come over this weekend if you will.2011年重慶卷Why didnt you come to Simons party last night?I want to, but my mom simply wouldnt let me out so late.2、表示請求would比will更委婉、客氣Will you come this way?Would you please help me?3、表示傾向性

19、、習(xí)慣性、必然性；否定結(jié)構(gòu)“不肯、不能”will用于現(xiàn)在，would 用于過去 “注定會、總是、老是”Boys will be boys.（傾向性）If today is Monday,tomorrow will be Tuesday.（必然性）She will sit there for hours,waiting for her son to come home.（習(xí)慣性）Oil and water will not mix.（必然性）When he was young, he would often swim in this river.（過去的習(xí)慣性）（九）need的用法表示“需要”。

20、可作為情態(tài)動詞和及物動詞。作情態(tài)動詞時，常用于否定句、疑問句、條件句中；作實義動詞不受限制。1、作情態(tài)動詞：注意疑問句和否定句的構(gòu)成及答語。You neednt see him,but I must.Need I see him?No, you neednt./Yes, you must.2、作實義動詞：后面接名詞、代詞、不定式，動詞的ing形式All living things need water.He needs to see you.You dont need to see him.The windows need cleaning/to be cleaned.（十）dare的用法1、

21、表示“敢”，可作為情態(tài)動詞和及物動詞使用。作情態(tài)動詞的時候，常用在否定句、疑問句及條件狀語從句中。作為及物動詞的dare有過去形式。但是人稱沒有變化。He dared not to go out alone in the night.How dare you ask me such a question?If you dare speak to me like that again,you will be sorry.She dare not say what she thinks.2、dare作實義動詞時不受句式的限制He dares to accuse her of dishonesty.

22、Does he dare to cross the river?Yes, he does.I did not dare to move.dare to do3、否定句中有時可不帶toHe does not dare (to) answer.（十一）used to的用法表示“過去常常、過去是”，現(xiàn)在已經(jīng)不再如此了，沒有人稱和數(shù)的變化，常與過去的時間狀語連用，以及l(fā)ike,be等狀態(tài)動詞連用。China is no longer what it used to be.否定形式:usent或didnt use to一般疑問形式：1.將used提到主語前，或者用Diduse to?的形式（十二）hav

23、e to的用法表示“只好、不得不”，意思接近must但must更強調(diào)說話者的主觀意愿have to強調(diào)客觀上的必要性。have to 有時態(tài)、人稱的變化，其否定式、疑問式都要借助助動詞do構(gòu)成I have to be off now. My mom is expecting me.Do you have to leave soon?You wont have to get up early if you dont go to work tomorrow.（十三）be able to的用法接動詞原形，表示具體的能力，與can的用法相近。但can只用于一般現(xiàn)在時與一般過去時，be able to可

24、用于更多的時態(tài)。Are you able to type?He wasnt able to/couldnt understand the meaning of life.在一般過去時的肯定句中，could只表示具備某種能力，而be able to側(cè)重“有能力且成功地做成了某事”The maths problem were hard but I was able to work them out.這些數(shù)學(xué)題很難，但是我還是成功地把他們解出來了。1、He has stayed in America for ten years.He can be able to speak English very

25、 fluently.can2、They have to go to school on Sundays,havent they?haventdont3、You dont need tell them,I will tell them when I go by.need后加to （實義動詞+名詞、代詞、不定式、Ving）4、Dare you to tell your parents your school records.劃掉to （dare此時為情態(tài)動詞）二、情態(tài)動詞表推測的用法比較二、情態(tài)動詞表推測的用法比較must,can,could,may,might都可以表示對現(xiàn)在、將來或者過去的推測

26、，但是他們推測的語氣強弱不同，所用的句式也不同。mustcan couldmay might“可能性”從大到小排序1、must表示對一個事情的發(fā)生很有把握的推測，“一定、想必”。表示推測時只用在肯定句中。must+V.對現(xiàn)在的推測must have done對過去發(fā)生的事情的推測must be doing對現(xiàn)在正在發(fā)生的事情的推測He must be very tired, for he stayed up very late last night.Look at the light in his room!He must have come back already.My parents m

27、ust be doing their jobs in their office at the moment.2、can 表推測時通常用在否定和疑問句中。cant表示“不可能”，語氣上也是很有把握的推測1）cant 對現(xiàn)在或者將來情況的推測2）cant have done對過去發(fā)生的事情的推測3）cant be doing對正在發(fā)生的事情的推測Cant she be at home now?Mr.zhang cant be present at the meeting tomorrow, for he has gone to Beijing on business.He cant have slept trough all that noise last night.What can/could she be doing now?She may/might be doing her homework.She cant be sleeping so late. 3、may/mightmay/might表示推測時常用在肯定句和否定句中，分別翻譯為“可能會”“可能不會”。might表推測時語氣更委婉。1）may (not) be對現(xiàn)在或者將來情況的推測