八年上语法课件：情态动词讲解

1、Grammar: 情态动词情态动词本身有一定的意义本身有一定的意义无人称和数的变化无人称和数的变化通常不带通常不带to to 表示说话人的语气或情绪表示说话人的语气或情绪1.Ability (能力能力):Liu Xiang can run the 110m hurdle race within 13 seconds.can/could:1. can 一般表示与生俱来的能力一般表示与生俱来的能力或者一种客观可能性或者一种客观可能性,还可以表示还可以表示请求和允许请求和允许 。Learning English _ be difficult.canMan can not live without a

2、ir. _ I use your bike?Cancan/could: 2.在疑问句中，用在疑问句中，用could可表示请求，可表示请求，语气较委婉。语气较委婉。 _I smoke here? Yes, you _. No, you _Couldcancant/Im afraid notcan:否定推测，疑问推测否定推测，疑问推测 3. 3.表示惊异、怀疑、不相信的态度。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）（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

3、地粗心！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表示表示“无论无论怎样怎样也不过分也不过分”，“越越越好越好” 。你过马路的时候再小心也不为过。你过马路的时候再小心也不为过。 You cant be too careful while crossing the road. can/be able to区别区别:Edison always wondered why hens could hatch (孵孵) chickens while he was not ab

4、le to.Question: Are the two modal verbs interchangeable (互换互换) ? If not, why?can表示表示或或，而，而be able to更加强调更加强调或者或者，能做到的事情。能做到的事情。Sum up1. can 和和 be able to1) can (could) 表示能力、可能表示能力、可能, 只用于只用于现在时和过去时。现在时和过去时。2) be able to可以用于各种时态。可以用于各种时态。只用只用be able to的情况：的情况： a.表示将能够做某事时。表示将能够做某事时。will be able to do

5、 sth b. 表示过去成功地做了某事时表示过去成功地做了某事时,只能用只能用 was/ were able to do sth,不能用不能用could。eg: A big fire broke out in ABC hotel yesterday. Luckily, everyone _run out of the building.was able to2. She _ speak both English and French.can1. They will _ run this machine on their own in three months. A. can B. could

6、C. may D. be able to2. That big cinema _ seat 2,000 people. A. can B. should C. ought to D. is able toD A 3.(2007福建福建)My MP4 player isnt in my bag. Where _I have put it? A. can B. must C. should D. wouldA4. A left-luggage office is a place where bags _be left for a short time, especially at a railwa

7、y station. A. should B. can C. must D. willB5. Mike _ be a policeman, for he is much too short.A. neednt B. cant C. should D. mayBIm so tired! I have to do the training for at least 10 hours a day! 2.Obligation (义务义务):yet he must work hard to win the gold medal.Although Liu Xiang is so gifted in hur

8、dle raceought to/shouldhave tomustYour mother brings you up and takes good care of you, so when she is old, you _ look after her in return. A. can B. may C. have to D. must Shi Dongpeng might win a medal at the Olympic Games.Although the chance of winning a medal is small, Ill try my best! 3.Certain

9、ty (可能性可能性) :must 表示肯定的猜测，译为表示肯定的猜测，译为“肯肯定定”，不能用于否定句或疑问句。不能用于否定句或疑问句。This must be your pen.He must be doing his homework now.He must have arrived already.must 2. 表示表示“坚持坚持”（常用于固定句型：（常用于固定句型：if you must do sth. 如果你非得要做某事）如果你非得要做某事）如果你真的要走，那就悄悄离开。如果你真的要走，那就悄悄离开。If you must leave, do it quietly.4.Permi

10、ssion (允许允许):May I eat KFC if I win the gold medal?may/might:1. 表示许可。表示请求、允许时，表示许可。表示请求、允许时，might比比may的语气更委婉一些。的语气更委婉一些。 Might/May I use your computer? Yes, you can. No, you cant/mustnt. may/might:2.2.用于祈使句中表示祝愿。用于祈使句中表示祝愿。3.表示推测、可能（只用于肯定句，表示推测、可能（只用于肯定句，疑问句则要用疑问句则要用can或或could）。）。 祝你成功！祝你成功！ May you

11、 succeed. He may be very busy now. May you be happy all your life. 5.Making requests (提出请求提出请求):Can you help me with my training?I dont know how to use this equipment! will can could wouldinformalformal6.Making suggestions (提出建议提出建议):Shall we do the training in the morning?Its too hot to take exerci

12、se in the afternoon. shall:1.shall用于第一、第三人称疑问句中，表用于第一、第三人称疑问句中，表示说话人征求对方的意见、向对方请示示说话人征求对方的意见、向对方请示或提供帮助或提供帮助 。1.Shall we begin our lesson? 2.When shall he be allowed to leave hospital? 3.Shall I carry this bag for you?shall:2.shall用于第二、第三人称的陈述句，表用于第二、第三人称的陈述句，表示命令、警告、允诺或威胁。示命令、警告、允诺或威胁。 You shall fa

13、il 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。等我读完这本书，就会给他的。 He shall have the book when I finish it.警告警告威胁威胁允诺允诺7.Making offers (提供帮助提供帮助):Dont worry, dear, I will wash them right away.Mom, my dirty clothes have been piled up! I dont have timewill/would:1. 表示

14、请求、建议等，表示请求、建议等，would比比will委委婉客气。婉客气。Sentence patterns Would you please Would you mindWould ratherWould you likewill/would:2.2.表示意志、愿望和决心。表示意志、愿望和决心。 I will never do that again. 3.可表示经常性、习惯性、倾向性。翻译为可表示经常性、习惯性、倾向性。翻译为“经常、惯于、总是经常、惯于、总是”。1).The old man _have a smoke under a big tree every afternoon aft

15、er he finished his farm work. would8.Giving advice (提出意见提出意见):You should not/ought not to eat so much before running.How delicious!should:1.should表示劝告、建议、命令，其同表示劝告、建议、命令，其同义词是义词是ought to；在疑问句中，通常用；在疑问句中，通常用should代替代替oughtto。Should I open the window? 我们应当要相互学习。我们应当要相互学习。 We should learn from each oth

16、er. ought to have done sth.should have done sth.本应该做某事本应该做某事,而事实上并没有做而事实上并没有做; 否定否定句表示句表示“不该做某事而做了不该做某事而做了”。You ought to (should) have beenmore careful in this experiment. He ought not to have thrown the oldclothes away.(事实上已扔了。事实上已扔了。)注注: ought to 在语气上比在语气上比should 要强。要强。should:2.情态动词情态动词should用于第一人称时可以表用于第一人称时可以表示说话人的一种谦逊、客气、委婉的语示说话人的一种谦逊、客气、委婉的语气。气。 RoseSure.