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,*,单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,Grammar,Modal verbs,第1页,情态动词使用方法,情态动词,两,个主要使用方法是:,1.表示:,判断、推测,_,2.表示:,语气,_,第2页,二情态动词包含:,can,may,must,could,might,need,dare,shall,should,will,would,ought to,have to,第3页,三情态动词特点:,1.无人称和数量改变。,2.不能单独使用做谓语,必须要使用情态动词+do结构。,3.情态动词过去式并不只是表示过去时态,还能够是一个委婉语气。,第4页,四can may must 使用方法,A.can may must在判断句式中,表示推测,must:,有把握,语气必定,推断有依据,只有必定形式,。如:,Look at his face.He_ be very angry.,Look at the clouds.It_ rain sooner or later.,must,must,第5页,can:,表示否定或疑问判断,。,如:,1)-Is Jack on duty today?,-It,cant,be him.Its his turn tomorrow.,2),Can,this be true?,第6页,may:,表示推测和可能。不用于疑问句,句子中总会有不确定信息(Im not sure.)如:,1)Im not sure.He,may,come.,2)He,may,be very busy now.,第7页,以上都是对现在或未来推断,假如是对过去推断会是怎样呢?Lets have a try.,1)The road is wet.It,must have rained,last night.,2)-Do you know where David is?I couldnt find him anywhere.,-Well.He,cant have gone,far.His coat is still here.,第8页,B.can may must表示语气使用方法,I.can/could 使用方法,can/could:表示能力、请求和许可,Man,cant,live without air.,Can,I go now?,Can,you finish this work tonight?,Can/Could,you say it again?,第9页,注意:,1)could也能够表示请求,语气比较委婉,主要用于疑问句,不能用于必定句,答语应该用can。如:,-,Could,I come to see you tomorrow?,-Yes,you,can,.,(否定,No,Im afraid not,.),第10页,2)can 表示能力时,还能够用be able to代替。如:Ill not be able to come this afternoon.,但当我们表示“某件事已成功”时,应该用“was(were)able to”,而不用“could”,No one was killed in the fire.All the people,were able to,escape.,He,was able to,go to the party yesterday evening and he enjoyed himself very much.,第11页,can 还能够表示惊异或怀疑。,How,can,you be so careless.,Can,this be true?,第12页,II.may/might 使用方法,1.表示许可。might 比may语气愈加委婉,否定回答时能够使用cant 或mustnt,表示“不能够”、“禁止”、阻止。,1)-,May,I take this book out?,-Yes,you,can,.,(-No,you,cant,./No,you,mustnt,.),第13页,2.用于祈使句中表示祝福。,May,you succeed!,3.与一些固定词组搭配,may as well,might as well+do,Its getting dark.We may as well walk home.,I may as well have a rest first.,第14页,III.must have to 使用方法,1.表示必须、必要。,You,must,come in time.,2.must引出问句,假如是否定回答要用,neednt,或,dont have to,.,-,Must,we hand in our homework today?,-Yes,you,must,.,No,you,dont have to,.No,you neednt,.,3.,Must,you play the piano at midnight?,第15页,4.must 和have to 区分,a.must表示,说话人主观看法,,而have to,则往往强调客观需求,。,This play is not interesting.I really,must,go now.,I,had to,work when I was your age.,b.must,只表示现在,,have to,则有更多时态改变,。,c.must,能够表示推断,,而have to,则不能,。,d.问询对方意见时,应该使用must,Must,I clean all the rooms?Yes you must.,第16页,IV.dare 和need 使用方法,1.dare 做情态动词时,主要用于疑问句、否定句和条件从句,普通不用于必定句。,How,dare,you say Im unfair.,He,darent,speak English before such a crowd,dare he?,2.need表示“需要”或“必须”,做情态动词时仅用于否定或疑问句中,在必定句普通用must,have to,ought to或should 代替。,You,neednt,come so early.,第17页,IV.dare 和need 使用方法,3.dare,need惯用作实义动词,有时态、人称和数改变。所不一样是作实义动词在必定句中,要用dare to/need to如:,He,needs to,finish it this evening.,第18页,V.shall/should 使用方法,1.shall 用于第一人称,表示征求对方意见。,What,shall,we do this evening?,2.shall用于第一、第三人称疑问句中,表示征求对方意见或向对方请求。,When,shall,he leave the hospital?,Shall,we begin our class?,第19页,V.shall/should 使用方法,3.shall用于第二、第三人称,表示说话人给对方命令、警告、允诺或威胁。,He,shall,be punished.(威胁)You,shall,fail if you dont work harder.(警告),He,shall,have the book when I finish reading.(允诺),All the candidates,shall,be seated before the papers are handed over.(命令,要求),第20页,V.shall/should 使用方法,4.should表示劝说、提议、命令。能够和ought to通用。,You,should,go to class right now.,Should还可表示对客观情况看法,按常理,约定情况,“理应该”,The pictures,should,be ready by 12 0clock.,The car,should,get repaired by tomorrow.,You practised a lot for the driving test,so there,shouldnt,be any problem for you.,He,should,come by 2 0clock.,第21页,V.shall/should 使用方法,5.should have done,You,should have finished,your homework last night,but actually you didnt.,You,shouldnt have told,lies to your mum.,第22页,V.shall/should 使用方法,6.should与how,why连用表示对某事不能了解,感到意外,惊异等,“竟会”“竟然”,How,should,you be so rude to your friend?,He is on time for everything.,How should,he be so late for the important meeting?,7.表“万一”,If things,should,change suddenly,please let me know.,If it,should,rain tomorrow,youd better bring your umbrella.,第23页,VI will/would使用方法,1.表示请求、提议would 比will委婉客气。,Would,you pass me the book?,2.表示意志、愿望和决心,I,will,help you,please dont worry.(表意愿),They asked us if we,would,do that again.I,will,never do that again.,第24页,VI will/would使用方法,3.would 能够表示过去重复发生动作或某种倾向,would表示过去习惯比used to 正式,而且没有“现在无此习惯”含义。,During the vacation he,would,visit me every week.,The wound,would,not heal.,第25页,系列练习:,(见学案),第26页,第27页,
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