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1、Unit2 Grammar and Usage,Modal verbs,can/could:,1. can 一般表示与生俱来的能力或者一种客观可能性,还可以表示请求和允许 。,Learning English _ be difficult.,can,Man can not live without air.,_ I use your bike?,Can,can/could:,2.在疑问句中，用could可表示请求，语气较委婉。, _I have the television on? Yes, you _. / No, you _,Could,He asks if he _ smoke here
2、.,could,can/may,cant/Im afraid not,can/could:,3.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?,can/could:,4. can never/canttoo表示“无论怎样也不过分”，“越越好” 。,你过马路的时候再小心也不为过。,You cant be too careful while crossin
3、g the road.,Attention:,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。,Attention:,can/be able to区别:,A b
4、ig fire broke out in ABC hotel yesterday. Luckily, everyone _ run out of the building.,was able to,2. She _ speak both English and French.,can,Attention:,advisability,necessity,ought to/should,have to,must,Your mother brings you up and takes good care of you, so when she is old, you _ look after her
5、 in return.,A.can B.may C.have to D.must,Attention:,very uncertain,almost certain,might,should,must,may,could,ought to,will,1.He _ be at home.,2.He _ be at home, for he just called me from his home 15 seconds ago.,A.may B.might C.must,A.may B.might C.must,(can),must 表示肯定的猜测，译为“一定”，不能用于否定句或疑问句。This m
6、ust be your pen.He must be doing his homework now.He must have arrived already.,must,must,2. 表示“坚持”（常用于固定句型：if you must do sth. 如果你非得要做某事）,如果你真的要走，那就悄悄离开。,If you must leave, do it quietly.,Attention:,They_ be doing the experiment in the lab.Why？Because the lights are still burning.,A.could B.can C.m
7、ust D.would,may/might:,1. 表示许可。表示请求、允许时，might比may的语气更委婉一些。, Might/May I use your computer? Yes, you can. /No, you cant/mustnt.,may/might:,2.用于祈使句中表示祝愿。,3.表示推测、可能（只用于肯定句，疑问句则要用can或could）。,祝你成功！,May you succeed.,He may be very busy now.,May you be happy all your life.,5.Making requests (提出要求):,Can you
8、 help me with my training?,I dont know how to use this equipment!,will can could would,informal,formal,6.Making suggestions (提出建议):,Shall we do the training in the morning?,Its too hot to take exercise in the afternoon.,shall:,1.Shall用于第一、第三人称疑问句中，表示说话人征求对方的意见、向对方请示或提供帮助 。,1.Shall we begin our lesso
9、n? 2.When shall he be allowed to leave hospital? 3.Shall I carry this bag for you?,shall:,2.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。,You shall fail if you dont work harder. He shall be punished according to the rule. 等我读完这本书，就会给他的。,He shall have the book when I finish it.,警告,威胁,允诺,7.Making offers (提供帮助):
10、,Dont worry, dear, I will wash them right away.,Mom, my dirty clothes have been piled up! I dont have time,will/would:,1. 表示请求、建议等，would比will委婉客气。,sentence pattern,Would you please,Would you mind,Would rather,Would you like,will/would:,2.表示意志、愿望和决心。,I will never do that again.,will/would:,3.可表示经常性、习
11、惯性、倾向性。翻译为“经常、惯于、总是”。,1).The old man _have a smoke under a big tree every afternoon after he finished his farm work.,would,2).门就是打不开 !,The door wont open.,will/would:,Attention:,I will go to the park with you tomorrow if you will offer me lunch.,Question: Is this sentence correct? Why?,情态动词,表示 “意愿”,
12、should:,1.Should表示劝告、建议、命令，其同义词是ought to；在疑问句中，通常用should代替oughtto。,Should I open the window?,我们应当要相互学习。,We should learn from each other.,should:,2.情态动词should用于第一人称时可以表示说话人的一种谦逊、客气、委婉的语气。,RoseSure. By the way, who is your idol?JackLiu Xiang, I should say.,I should advise you not to do that again.,3.
13、should表示意外或惊讶 常译为 “居然，竟然”。 I cant believe such a gentleman should be so rude to the old. 我不敢相信这样一个绅士居然对老人如此无礼。,should:,4. should 表示猜测时，一般指按经验或逻辑判断，翻译成“照说应该，估计，想必”,should:,-When can I come for the photos ? I need them tomorrow afternoon. -They _be ready by 12 : 00 . A. can B. should C. might D. need,
14、To be continued,三. “情态动词+have done”的用法,（1）must have done对过去某事的十分肯定猜测（2）may/might have done对过去某事的可能性猜测（3）cant/couldnt have done对过去某事的否定猜测（4）should/ought to have done过去应该做而未做（5）shouldnt/oughtnt to have done 过去不应该做而实际上做了（6）neednt have done 本没有必要做的事实际却做了（7）could have done 本来能够做的（有能力做）事实际却未做到,Lets have a
15、 try!,Practice,With so much work on hand, you _to see the game last night. A. mustnt go B. could have goneC. shouldnt go D. shouldnt have gone,2. There was plenty of time. She _.A. mustnt have hurried B. couldnt have hurriedC. must not hurry D. neednt have hurried,Practice,3. I saw Mary in the libra
16、ry yesterday. -You_ her. She is still abroad.A. mustnt see B. cant have seen C. mustnt have seen D. couldnt see,4. Aunt Mary_the train, otherwise she would have arrived here by now.A. must have missed B. should have missedC. had missed D. might miss,四. 可兼做行为动词的情态动词：need 、 dare,情态动词 (+动词原形),行为动词,need
17、,dare,1.无人称和数的变化;,2.尤其用于：,*否定句及疑问句中;,*在if/whether之后;,*或与hardly, never, no one, nobody连用;,3.常以neednt 和darent 的形式出现;,4.dare有其过去时dared.,多用于肯定句; (sb.) need to do dare to do(sth.) need to be done (sth.) need doing,He darent speak English before such a crowd, dare he?,判断正误:,He darent to speak English before such a crowd, did he?,These dishes need be cleaned carefully.These dishes need to be cleaned carefully.These dishes need cleaning carefully.,五. 表示否定的情态动词的用法: 部分情态动词的否定式是情态动词中的考点之一。,mustnt 不准, 禁止 neednt 没必要 ( = dont have to )cant 不能; 不可能may not 不可以; 可能不shouldnt 不应该 ( = ought not to ),Thank you!,
