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1、关于情态动词课件第一页，讲稿共二十二页哦Teaching Goals Modal Auxiliary 情态助动词情态助动词 Can,could May,might Will,would Should,shall Dare,dared,need,needed Must,have to Semi-auxiliary 半助动词半助动词第二页，讲稿共二十二页哦Can,could1.表示能力，与表示能力，与 be able to 同义。在肯定句中，同义。在肯定句中，could只表示过去有只表示过去有“能力能力”做，做，was were able to 表示过去有能力且确实做到了。表示过去有能力且确实做到
2、了。She could play the piano when she was only six.He was able to translate the article without a dictionary.2.表示惊异，怀疑，和可能性。多用于表示惊异，怀疑，和可能性。多用于否定句和疑问句否定句和疑问句。Can it be true?How can you be so rude!3.表示请求和允许，与表示请求和允许，与may同义，相当于同义，相当于be allowed to.常用语口语中。常用语口语中。You can smoke in this room.Could I borrow y
3、ou dictionary?第三页，讲稿共二十二页哦Can,could4.用于一些固定句型用于一些固定句型a.Cannot(can never)too怎么也不过分怎么也不过分 You can never do the work too well.b.Cannot(couldnt)help+doing 情不自禁情不自禁 When I heard what the litter girl said I couldnt help laughing.c.Can but 只好，不得不只好，不得不 We can but agree with her.d.Not if one can help it 如果可
4、能就不做某事如果可能就不做某事 He wont fight with other if one can help it.第四页，讲稿共二十二页哦Can,couldCan 与与 be able to 的比较的比较(1)表示能力时两者意义相同表示能力时两者意义相同 No one can/is able to do it.(2)Be able to 表示表示“通过通过努力努力成功地做某事成功地做某事”，相当于，相当于manage to do sth.succeed in doing sth.With the help of the firemen,they were able to leave th
5、e burning house.(3)Can 常指现在，也可用于过去时态，但不用于完成和将来时态。常指现在，也可用于过去时态，但不用于完成和将来时态。Be able to 可用于可用于各种时态，也可用于不定式或名词短语中。各种时态，也可用于不定式或名词短语中。We ought to be able to live on my salary.第五页，讲稿共二十二页哦May,might(1)可能性可能性 I may be busy from tomorrow on.(2)表示允许表示允许 Id like to have a smoke here if I may.(3)may间或用来表示间或用来表
6、示祝愿祝愿，也常用于表示目的或让步的状语从句中，也常用于表示目的或让步的状语从句中:May that day come soon.May you succeed in winning the first prize in the game.注意注意：在回答以：在回答以may引导的问句时，一般说来避免使用引导的问句时，一般说来避免使用may，以免显得太严厉、或不太，以免显得太严厉、或不太客气，而改用其他方式。例如：客气，而改用其他方式。例如：-May I come in?-Yes,please.-Sure./Certainly.-Please dont.-No,you mustnt.第六页，讲稿
7、共二十二页哦May,mightMay 的其他用法的其他用法(1)may well+原形原形 理所当然理所当然 You may well say so.(2)May as well=had better 最好最好 We may as well stay where we are.(3)May as well+原形原形+as+原形原形 与其。不如，最好。不要。与其。不如，最好。不要。You might as well throw your money away as lend it to him.(4)May but 我承认。是事实，但是。我承认。是事实，但是。It may rain tomorr
8、ow,but we re been determined.第七页，讲稿共二十二页哦Will,would 1）用于第二人称疑问句，表示）用于第二人称疑问句，表示请求请求（在这种用法中（在这种用法中would使语气更为客气、委婉）使语气更为客气、委婉）Will you tell her that Ill be back in twenty minutes?2）用于表示）用于表示愿望愿望Go where you will.I will pay you at the rate you ask.3）表示）表示习惯、倾向习惯、倾向（可译成（可译成总是会、老是，等总是会、老是，等）Sometimes the
9、 cat will lie there all afternoon 4）表示）表示猜测猜测（可译成（可译成一定是一定是、想必、想必，等，等）This will be the house youre looking for.第八页，讲稿共二十二页哦Will,would 5）would常用于虚拟条件句，表示与事实相反或不太可能实现的情况常用于虚拟条件句，表示与事实相反或不太可能实现的情况But for your help we would have been late.6)Would 表示过去的习惯性动作或某人的一典型动作，又使人厌烦的感觉。表示过去的习惯性动作或某人的一典型动作，又使人厌烦的感觉
10、。He would go swimming in summer when he was in the countryside.注意：注意：used to,would 用法比较用法比较(1)Used to 不能跟表示确定时间段的状语连用，不能跟表示确定时间段的状语连用，would 可以。可以。He used to work here for twenty years.()第九页，讲稿共二十二页哦Will,would(2)used to 可以表示过去的习惯动作后可以表示过去的习惯动作后状态状态，而，而would 只表示过去的习惯动作。只表示过去的习惯动作。There would be a buil
11、ding at the street corner,but it has been pulled down.()There used to be a building at the street corner,but it has been pulled down.()(3)Used to 强调过去的行为强调过去的行为同现在的对比同现在的对比，含有，含有“过去如此，现在已不再这样了过去如此，现在已不再这样了”之意。之意。Would 仅表示过去习惯性的动作，没有与现在相比之意。仅表示过去习惯性的动作，没有与现在相比之意。People used to believe that the sun mo
12、ves round the earth.()People would believe that the sun moves round the earth.()第十页，讲稿共二十二页哦Should,shall 1、Shall/should1)、第一、三人称疑问句中表示、第一、三人称疑问句中表示“请求或征求对方意见请求或征求对方意见”Shall I get you a cup of coffee?2)、第二、三人称陈述句中、第二、三人称陈述句中(1)、表示、表示允诺允诺“会（得到）会（得到）”You shall have my answer tomorrow.(2)、表示、表示命令命令/警告威胁
13、警告威胁“这回必须这回必须”He shall be published.3)Shall 用于所有人称，表示用于所有人称，表示规章，法令，预言规章，法令，预言等等 It has been announced that candidates shall remain in their seats until all the papers have been collected.第十一页，讲稿共二十二页哦Should,shall 4)Shall/should 表示意愿，意志表示意愿，意志用于第一人称，用来表示说话人的意图，同用于第一人称，用来表示说话人的意图，同will可以互换。可以互换。We sh
14、ant/wont go if it rains.b.一般用于肯定句中的第二三人称，表示说话人的意愿，在疑问句中，表示征询听话一般用于肯定句中的第二三人称，表示说话人的意愿，在疑问句中，表示征询听话人的是否愿意。人的是否愿意。He shall get his money.5)Should 表示说话人的惊奇、愤怒、失望等特殊情感表示说话人的惊奇、愤怒、失望等特殊情感Its surprising that Mary should love such a person as Jack.Its strange that Its unthinkable that Im sorry that第十二页，讲稿共
15、二十二页哦Must,have to must的用法的用法（1 1）表示推测）表示推测“可能性可能性”时，意思是时，意思是“一定、准是一定、准是”，语气较肯定，较有把握。，语气较肯定，较有把握。He must be American.=It is certain that he is American.He must be American.=It is certain that he is American.他准是个他准是个美国人。美国人。（2 2）mustmust表推测只能用于肯定句。表推测只能用于肯定句。如表示如表示“一定不、肯定不一定不、肯定不”的意思时，应用的意思时，应用cant,ca
16、nt,如询问某种可能时，应用如询问某种可能时，应用cancan。He must know my address.He must know my address.（一定）（一定）He He cantcant know my address.know my address.（一定不）（一定不）Can he know my address?Can he know my address?（询问可能性）（询问可能性）第十三页，讲稿共二十二页哦Must,have to 3 3）在反意疑问句中，当附属部分含有表示推测意义的）在反意疑问句中，当附属部分含有表示推测意义的mustmust时，疑问部分的时，疑问部
17、分的助动词应助动词应与与mustmust后面的动词后面的动词在非推测情况下的用法在非推测情况下的用法保持一致保持一致。He must He must bebe a worker,a worker,isntisnt he?he?（现在）他准时个工人，是吗？（现在）他准时个工人，是吗？You must You must have learnedhave learned English for many years,English for many years,haventhavent you?you?（完成时）你一定学了好多年英语，是吗？（完成时）你一定学了好多年英语，是吗？比较：比较：It mu
18、st It must have rainedhave rained last nightlast night,didntdidnt it?it?（过去）昨晚一定下雨了，是不是？（过去）昨晚一定下雨了，是不是？He must He must have arrived have arrived by yesterday morning,by yesterday morning,hadnt he?hadnt he?第十四页，讲稿共二十二页哦Dare,daredDare/daredDare/dared1 1、情态动词用于、情态动词用于否定、疑问句否定、疑问句；条件从句中；条件从句中 1.Dare yo
19、u go here alone?1.Dare you go here alone?2.How dare you do such folish things?2.How dare you do such folish things?3.I wont allow you to swim in the river,even if you dare do it.3.I wont allow you to swim in the river,even if you dare do it.2 2、做实意动词后、做实意动词后加不定式加不定式 I have never dared I have never d
20、ared to to tell him about it.tell him about it.第十五页，讲稿共二十二页哦Dare,dared情态动词情态动词使役动词使役动词肯定式肯定式He dared to run.否定式否定式He darent run.He doesnt dared(to)run.肯定疑问句肯定疑问句Dare we run?Do we dare(to)run?否定疑问句否定疑问句Dare he not run?Doesnt he dare to run?第十六页，讲稿共二十二页哦Need,neededNeed/neededNeed/needed1 1、情态动词用于否定句，疑
21、问句、情态动词用于否定句，疑问句 He neednt worry about it.He neednt worry about it.2 2、实意动词用法似、实意动词用法似dare,dare,用加不定式用加不定式3 3、need need 作情态动词提问，回答肯定的用作情态动词提问，回答肯定的用must,must,否定用否定用needntneedntNeed we work late today?no,but we Need we work late today?no,but we mustmust tomorrow.tomorrow.Need I tell Elizabeth at once
22、?no,you Need I tell Elizabeth at once?no,you neednt neednt tell her just yet.tell her just yet.4 4、need+not+have+p.p need+not+have+p.p 表示表示“本来不需要做而做了。本来不需要做而做了。You neednt have bought that house.You neednt have bought that house.第十七页，讲稿共二十二页哦Need,needed情态动词情态动词使役动词使役动词肯定式肯定式You need to be careful.You
23、 need to be careful.否定式否定式You You neednt beneednt be so worried.so worried.You You dont need todont need to be so be so careful.careful.肯定疑问式肯定疑问式Need INeed I say it again?say it again?Do I needDo I need to say it to say it again?again?否定疑问式否定疑问式Neednt himNeednt him come?/Need he come?/Need he not c
24、ome?not come?Doesnt heDoesnt he need to come?/need to come?/Doesnt he not need to Doesnt he not need to come?come?第十八页，讲稿共二十二页哦表示推测的用法词形肯定式否定式疑问式Must必定，必然/Will很可能，大概不会，不该会吗？Would可能性比will小语气比wont 弱语气比will弱Should确定或可能/Ought to/Can/不可能有可能吗？Could可疑的可能不可能语气比can弱May也许，说不定，或许可能不/might比may小比 may not 还弱/第十九页
25、，讲稿共二十二页哦表示推测的用法一一.should have done.should have done过去本来应该（过去本来应该（而实际上并没有而实际上并没有)should not have done should not have done 本不应该本不应该 而实际上却已经而实际上却已经”1 1、We should have studied last night,but we went to the concert We should have studied last night,but we went to the concert instead.instead.二二.could ha
26、ve done.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。1 1、I I could have runcould have run 100 metres in 12 seconds.100 metres in 12 seconds.（实际上没能实际上没能）2 2、If you could have finished the task in timeIf you could have finished the task in time，you could have been promoted.you could have been promo
27、ted.（实际上没有被提升）（实际上没有被提升）三、三、need not have doneneed not have done它表示过去已做的事，事实上没有必要。它表示过去已做的事，事实上没有必要。1 1、I I need not have got upneed not have got up so early.so early.（事实上早已起床事实上早已起床）第二十页，讲稿共二十二页哦表示推测的用法2 2、I need not have waited for the train for an hour.I need not have waited for the train for an
28、hour.（事实上已经等了一个小时）（事实上已经等了一个小时）四、四、would have done would have done 用在虚拟语气中用在虚拟语气中 表示与过去事实相反之假设的结果，常与表示与过去事实相反之假设的结果，常与if if 的条件句连用。的条件句连用。1.I 1.I would have helpedwould have helped you you ifif I I had knownhad known of your difficulties.of your difficulties.（而实（而实际上没有帮助你）际上没有帮助你）2.If it hadnt rained yesterday,we would have gone out for a walk.2.If it hadnt rained yesterday,we would have gone out for a walk.（实际上没（实际上没有去）。有去）。第二十一页，讲稿共二十二页哦感谢大家观看感谢大家观看第二十二页，讲稿共二十二页哦