情态动词can和could的用法

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,*,Unit2 Grammar and Usage,Modal verbs,Lead-in,We,can,bethereontimetomorrow.,May,Icome in ?,Shall,webeginnow?,You,must,obeytheschoolrules.,Learning objectives,1.Master,basic usage,of modal verbs ( can/could).,2. Finish the relevant exercises.,Self-study guidance (1 ),Refer to the workbook on P49 and find out the definition of modal verbs and consider how many modal verbs you know.,情态动词的定义,:,情态动词是一种本身有一定的词义,表示说话人的,情绪,态度或语气,的动词,但,不能单独作谓语,只能和其他动词原形构成谓语。,How many modal verbs,do you know?,can could,may might,shall should,must,will would,ought to,have to,dare (darent),need (neednt),used to,modal verbs,can/could,的 用法,二,情态动词的语法,功能,We can use modal verbs to talk about:,ability,certainty,permission,obligation,make,requests,make,suggestions,make,offers,give,advice,能力,义务,责任,确,定性,允许,提出,请求,提出,建议,提供,帮忙,提出,忠告,Modal verbs:,general introduction,用法一：,Ability (,能力,),Liu Xiang,can,run the 110m hurdle race within 13 seconds.,1.Now many of us _(,能）,speak,English quite well, but a few years ago, we _ (,不能,can,指现在的能力,could,表示过去的能力,2.Now many of us _ (,能）,speak English quite well, but a few years ago, we _(,不能,can,couldnt,are able to,werent able to,be able to,也可表示能力，它的用法，,要比,can/could,要正式一些,但不常用。,can/be able to区别:,Edison always wondered why hens,could,hatch (孵) chickens while he,was not able to,.,Question: Are the two modal verbs interchangeable (互换) ? If not, why?,can表示,与生俱来的能力,或,一种客观可能,，而be able to更加强调,通过后天的学习和努力获得的能力，,或者,在某个客观的场合和背景下,，能做到的事情。,The fire spread through the hotel very quickly but everyone _ get out.,A .had to B. would,C. could D. was able to,D,be,able to,do,sth,.,= manage,to do sth.,= succeed in doing sth.,3. Im sorry I _ _ _ _(,不能）,play tennis with you,recently,.,4. Its nice,to,_ _ _(,能）,attend the lecture.,5. Wang Gong _ _ _ _ (,可能,能）,win the chess game.,havent been able to,be able to,might be able to,be able to,用于不同的时态,2.,可用在不定式之后,3.,可用在情态动词之后,They,will,_ run this machine on their,own in three months.,A. can B. could C. may D. be able to,D,A,试试吧！,用法二：表示允许（,permission),-Can/Could,I have a look at your new pen ?,-Yes ,you,can,/ No , you,cant,.,-Could I borrow your dictionary ?,-Yes , of course you _,A might B will C can D could,C,can / could / may / might,Permission,允许,informal / spoken,formal / written,Can/May/Could/Might I come in?,Yes , you can/may,Yes ,please.,No , you mustnt .,Please dont .,No ,you may not.,could,常用于疑问句中，比,can,更加委婉，表示礼貌。用于回答时，常用原形,can,或者,may ,不可再用过去式,could,或,might,用法三,.Making requests (,提出要求,),Can,you help me with my training?,I dont know how to use this equipment!,Will / Can/ Could/Would,you help me with my training?,Yes, I,will/can/can/will,.,will / can / could / would,make requests,informal,formal,用法四,could,用于表示的推测（表示可能）,1,）,We could go there this summer.,（对,将来,的推测）,2,）,He couldnt have enough money for a new car now.,(,对,现在,的推测）,3,）,He couldnt be singing.,（对,进行,的推测,),4) Could he have heard the news ?,(,对,过去,的推测）,certainty,very uncertain,almost certain,might,should,may,could,ought to,will,can,推测（表示可能）一般只用于,否定句,和,疑问句,，而,could,一般无此限制。,1,）,We could go there this summer.,（肯定句 对将来的推测）,2,）,He couldnt/,cant,have enough money for a new car.(,否定句，对现在的推测）,3,）,He couldnt /,cant,be singing.,（否定句，对进行的推测,),4) Could/,Can,he have heard the news ?(,疑问句，对过去的推测）,1.- Hows your new babysitter(,保姆,) ?,（,2011,）,-We,_,ask for a better one. All our kids love her so much.,A. should B. might C. mustnt D. couldnt,2.Mary _ be in Paris , for I saw her in the town only a few minutes ago.,A mustnt B cant C shouldnt D may not,could,推测的语气比,can,推测的语气较弱,can,推测的把握性很大。,B,D,can,表示理论上或是逻辑上判断的,可能性,，一般翻译成,“会”。,常用在,肯定,句中,It is usually warm in my hometown in March, but it _ be rather cold sometimes.,A must B can C should D would,That big cinema _ seat 2,000 people.,can B. should,C. ought to D. is able to,B,A,用法五：,can/could,:,1.,表示惊异、怀疑、不相信的态度。（主要用在否定句、疑问句或惊叹句中）,Hes such a nice person that he _ commit the crime,.,cant,你怎么会如此地粗心！,How,can,you be so careless!,Can,this be true?,Why/How + should/can,结构表示说话人对某事不能理解，感到意外、惊异。“竟会”。,Why should you be so late today,？,How can you be so careless?,其他惯用法,A.,cant/can never too= cant/ can neverenough,无论怎么,也不为过,越,越好。,You cant be too careful when crossing the street.,B.,cant but do,sth,= have no choice but to do,sth,= cant choose but do,sth,= have to do,sth,不得不做某事,C .,cant help to do,sth,= cant help do,sth,.,不能帮忙做某事,cant wait to do,sth,.,迫不及待做某事,cant help doing,sth,.,情不自禁做某事,cant help but do,sth,.,忍不住做某事。,cant afford to do,sth,.,不能承担得起做某事,cant tell A and/from B,不能区分,A,和,B,Lets have a try!,Finish the exercises about the workbook on,P49,Check the answers:,1. A,2. B,3. A,4. D,5. A,6. B,Homework,preview the modal verbs:,may/might,must,shall,