1、will,would1)用于表示意志或意愿。will指现在，would指过去。e.g.I will never do that again.They said that they would help us.2)表示“请求；建议”。用would比will委婉、客气些。e.g.Will you please take a message for him?Would you please pass him the book？1.情态动词的基本用法3)表示习惯性动作，“总是”“惯于”，will指现 在，would指过去。e.g.Fish will die without water.4)表示预料或猜
2、想。e.g.It would be about ten when he left home.5)表示规律性的“注定”用will。e.g.People will die without water or air.can,could1)表示能力。e.g.My grandma is well over eighty,but she can read without glasses.2)表示客观可能性。e.g.Accidents can happen to any drunken driver.3)表示请求和允许。e.g.Can I have a look at your design?Yes,of
3、course you can.4)表示惊讶、怀疑、不相信的态度。（主要用于否定句，疑问句和惊叹句）。e.g.What can he be doing at this time of night?5)表示请求，口语中常用could代替can,使语气更委婉。e.g.Could you please help me with this furniture?may,might1)表示允许、许可。否定回答时，一般用mustnt，“禁止、阻止”。e.g.May I watch TV after supper?Yes,you may./No,you mustnt.2)表示请求、允许时，might比may的语
4、气更委婉；用May I？征询对方许可在语气上比较客气；用Can I？征询对方意见更常见。e.g.Might I use your telephone?Yes,please.May/Can I go home now?Yes,you may/can.3)表示可能性的推测，“或许，可能”，用might代替may时，语气显得更加不肯定，用于陈述句中。e.g.It may be true.She may come tomorrow.He might have some fever.4)may用于祈使句中表示祝愿。e.g.May you succeed！must1)表示“必须；应该”。以must开头的问
5、句，否定回答常用neednt或dont have to，肯定回答用must。e.g.You must come to school on time.2)表示有把握的推测，只用于肯定句中。e.g.You must be ill.I can see it from your face.3)表示“非要；偏要”。e.g.They are sleeping.Must you play the piano at this time？have to表示“必须；不得不”，强调客观需要，有时态，人称的变化。e.g.I cant see things clearly.I have to wear glasses.
6、shall1)用于第一人称，表示征求对方的意见。e.g.What shall we do next？2)用于第一、三人称的疑问句，表示说话人征求对方的意见和向对方请示。e.g.Shall we begin our lesson?Shall the driver wait？3)用于第二、三人称的陈述句，表示说话人给对方的命令、警告、允诺和威胁。e.g.You shall go with me.He shall be punished.should1)表示劝告或建议，“应该”。e.g.We should be strict with ourselves.2)表示推测，“可能”或“应该”。e.g.T
7、hey should have arrived by two oclock.3)用于第一人称表示说话人的一种谦逊、客气、委婉的语气。e.g.I should advise you not to do that.You are mistaken,I should say.4)用在if条件句中，表示可能性很小，但也不是完全不可能。e.g.Ask Tom to ring me up if you shouldsee him.5)Why/how+should，表示意外，惊异，“竟会”。e.g.Why should you be so late today？need表示“需要；必要”，用于否定句、疑问句
8、中，只有现在时，其他时态用have to的相应形式代替。e.g.You neednt ask him the question.Need I finish the work before ten?dare表示“敢；敢于”，主要用于疑问句、否定句和条件从句中，一般不用于肯定句(I dare say除外)。e.g.Dare you go alone there?The boy darent say so before the teacher.How dare he do such a thing？ought to1)表示“应该”。e.g.You ought to take care of him.
9、2)表示推测。e.g.He ought to be home by now.used to表示过去常常(现在已经不再)。e.g.There used to be a temple here.had better表示“最好”。e.g.You had better finish it now.【注意】could,should,might不一定与过去时间有关,而是表示可能性弱于与其相应的现在时形式;should/ought to表示推测时,表示确定或可能性大的合乎理想的情况或结果。need和dare用作实义动词时,有词形变化,变成否定句、疑问句时,要加助动词。如：You dont need to d
10、o it yourself.We should dare to give our own opinion.2.表示推测的情态动词的层次比较情态动词的“推测”功能。如：can,could,may,might,must皆可表示推测，使用时要注意以下几点：1)注意语气。语气较强用must,cannot,couldnt;语气较弱用may,might或can,could。2)注意句式。在肯定句中，一般用may,might,must;在否定句、疑问句中常用can,could。3)注意时态。表示对现在或将来的情况的推测，此时通常用“情态动词动词原形”结构；表示对现在或将来正在进行的情况进行推测，通常用“情态
11、动词进行体”结构；表示对过去情况的推测，通常用“情态动词完成体”结构。3.情态动词+have done1)must have done表示对过去情况的肯定推测。2)may/might have done表示过去可能发生过某事。3)could have done表示过去可能发生，但并未发生，含有埋怨或训斥之意；也可表示对过去可能发生的事情的一种推测。4)should/ought to have done表示过去本该做（某事）而事实上未做；should not/ought not to have done表示过去本不该做（某事）但事实上却做了，含有批评、责备之意。5)need have done表
12、示过去本来有必要去做（某事），但事实上没有做；need not have done表示过去本没有必要做（某事），但事实上做了。4.考查情态动词的特殊用法1)cannot/cant 与too/over/enough/perfectly/sufficiently等词连用，“越越”“无论怎样，也不为过”“决不会，够(过)”。2)cannot wait to do sth.“急于做某事”。3)may/might well动词原形“理应，有足够的理由”；may/might as well动词原形“还不如，不妨，还是的好”。4)must“偏要，硬要”；can用在肯定句中，可以表示客观上的可能性；shall
13、用在法律、条约、协定等文件中可以表示义务、规定等；should表示估计或推测上的“应该”，“可能，该，估计，按理应当”；will可以表示习惯性和倾向性，“惯于，老是，终归是”等。5)can/could与be able to辨析时态区别情态动词can只有两种时态形式,现在式can和过去式could,be able to有多种时态形式。语境结果区别could可以表示过去的能力,was/were able to表示经过一番努力后取得了成功,相当于manage to do或succeed in doing,而could没有这个含义。1.Ive prepared all kinds of food fo
14、r the picnic.Do you mean we _ bring anything with us?A.cant B.mustntC.shant D.neednt2.It was sad to me that they,so poor themselves,_ bring me food.A.might B.would C.shouldD.could3.Ive ordered some pizza,so we _ worry about cooking when we get home tired.A.cant B.dare notC.needntD.may not4.They were
15、 abroad during the months when we were carrying out the investigation,or they _ to our help.A.would have comeB.could comeC.have comeD.had come5.Life is unpredictable;even the poorest _ become the richest.A.shallB.mustC.need D.might1.As good friends,you _ us about your trouble earlier.If so,all of us
16、 could have given you a hand.A.should tell B.might tellC.might have told D.should have told2.According to school rules,all the students _ do sports for at least one hour every day during school time.A.might B.shallC.may D.need.选择填空。3.Artistic people can be very difficult to get on with sometimes.Wel
17、l,you _ know you married one.A.can B.mightC.need D.should4.You _ be so upset about the result.Keep working hard and you will do better next time.A.neednt B.mustntC.cant D.wont5.I have something important to tell John.But I cant find him.His cell phone is here,so he _ have gone too far.A.mustnt B.nee
18、dntC.wouldnt D.cant 6.Those smokers must be aware of the harm that secondary smoking _ cause to people around them.A.may B.mustC.should D.need.从方框内选用合适的情态动词并用其正确形式填空（包括否定形式）。1.Is David coming by train?He should,but he _ not.He likes driving his car.2.No reader _ remove a book from the library withou
19、t the permission of the librarian.3.The girl _ be Mary shes in New York.can,shall,may,should,need,mustmay shallcant4.That the well-dressed young man _ speak to you like that is quite astonishing.5._ I finish the job right now?Yes,you must.6.Must we hand in our exercise books today?No,you _.7.Havent
20、you seen the sign“No parking”here?Cars _ be parked here.should Needneedntmustnt8.Shall I inform her of the change of the meeting right now?I am afraid you _,in case he comes late for the meeting.9._ you be interested,Ill tell you the whole story.10.It was an easy test and he _ have passed,but he did
21、nt.mustShouldshouldIII.根据括号内的汉语提示补全下列句子。1.She _(不需要亲自来)a letter would have been enough.2.I lost your address,otherwise I _ _(早就写信给你了).3.They are always making trouble.I think its high time they _(被教训一顿了).neednt have come in personwritten to youwould havewere taught a lesson4.He insisted I _(应该打个车)an
22、d offered to pay for it.5.Your advice that she_ _(等到下周)is reasonable.6.I should not have made fool of you if I _(早想到你是认真的).7.If you had spent more time practicing making it before,you _ _(就能把它做得更好)now.(should)take a taxi(should)wait till nextthought you were seriousweekhadit much betterwould be able to make
