高一英语英语必修3Unit1语法情态动词 3课件

1、Modal Verbs Unit 114 九月 20222情态动词表示说话人的某种感情或语气，对某一动作或状态的某种态度。表示“需要、可以、必须、应当”等。 什么是情态动词？ (Modal Verbs)can/could, may/might, must/ have to, shall/should (ought to), will/would need, dare14 九月 20223情态动词的特点：1.情态动词自身都有一定的意义，但不能表示正在发生或已经发生的事情，只表示期待或估计某事发生。2.情态动词除ought和have外，后面必须接不带to的不定式。3.情态动词没有人称和数的变化,也

2、没有非谓语形式。14 九月 20224 1. can的主要用法是： A. 表能力 eg. The girl can dance very well. be able to 通过努力做成某事 He was able to reach Mount Qomolangma in 2000. B. 表示说话者的推测事物的可能性:(否、疑） eg. Can the news be true? C. 在口语中, can可以表示请求或允许： eg. Can I sit here? 1. can和could14 九月 202252. could的主要用法是： A. could 是can的过去式, 表示与过去 有

3、关的能力和推测: We all knew that the young man couldnt be a doctor. B. could可以代替can表示请求, 但语气较can客气、委婉:could 提问，答语用can -Could I borrow your pen?-yes, you can.can, could 和be able to的用法e.g.She can/be able to sing the song in English. This machine can make you feel comfortable.1.can, be able to都可表示“能力”Can的主语是人

4、或物,be able to的主语是人 can, could 和be able to的用法e.g. Well be able to finish the work soon. I havent been able to see the film.2.can只用于现在时和过去时(could)。 beableto可以用于各种时态。 could用于表示泛指过去的能力。 e.g. IcouldreadwhenIwasfour. Although the soldier was badly wounded, he was able to tell what had happened.3.表示特定的某一过去

5、能力或表示成功地做了某事时，只能用was/wereableto，不能用could。 e.g. Hewasabletoescape fromEuropebeforethewarbrokeout. Hewasabletoswimbeforehegottired. 表示过去的能力14 九月 20229may 常用来表示： 1. 在正式文体中表示请求、允许（比can正式）：: eg. May I come in ? You may go now. 2. 表示说话人的猜测: “也许” “可能”: 通常只用于肯定句和否定句中。The guest may arrive this afternoon.-Can

6、 he attend the meeting?-Yes, he_. I am not sure.2.may和mightmay14 九月 2022103. 表示祝愿,位于句首 eg. May you succeed! May you have a good journey! 4. may as well=had better do (最好做某事） Youd better take notes carefully. You may as well take notes carefully. 5.might 可用于指过去的行为或者表示可能性更小。e.g.他也许在做功课吧。He might be do

7、ing his homework now. 我问他我是否可以离开。I asked him if I might leave.I asked him “May I leave now?”14 九月 2022123.will和wouldwill是助动词还是情态动词？ will用于构成将来时是助动词。 eg. I will tell you something important. 我要告诉你一件重要的事情。 情态动词：1.表意愿或意志 I will never do it again. If you will marry me, whatever I have is yours, and mine

8、s is yours.14 九月 202213 2.提出 请求或建议 ,在疑问句中用于第二人称。 eg: If you want help, let me know, will you? Will you type this, please? 祈使句问句与答语一般用will Open the door, will you? - Please come to my party. - Yes, I will3. 表习惯或必然结果 Fish will die without water. I will go to see my former classmates on weekends. 14 九月

9、 202214would & used to (过去常常，习惯于）would 现在有可能做，也有可能不做used to 现在一定没有做There used to be a big tree.I would go to the library when I was free.I _ to cry when I was a child.used to14 九月 2022154.shall和should shall 用法 1. shall表征求意见，用于一三人称 疑问句中 Shall we go by train, Mom? Shall he attend the meeting?2.用于二 三人称

10、 的陈述句中，表威胁警告命令允诺等语气 You shall get a present when I came back. You shall be punished if you break the rules.14 九月 202216should 用法1. 表万一，多位于句首。 Should he come, I would let you know.2. “居然”，“竟然”,表说话人意料之外。 针对现在- + V原 针对过去- should have done To my surprise, he should be a thief. He should have lied to me

11、yesterday.e.g. Young people should learn how to use computers. Every citizen ought to obey law. You ought not to go.3. should常表示劝告、建议、命令，与ought to意义相近，但ought to多表示责任、义务，语气强烈。在疑问句中通常用should代替ought to。14 九月 2022185.must的主要用法1. 必须。 I must go home this Saturday. Ive got a cold, so I have to see a doctor

12、. -Must I stay here? -Yes, you must./ No, you neednt./you dont have to.mustnt 表禁止，不准，一定不要。 You mustnt play with fire. You mustnt take drugs. 14 九月 2022192. 表“偏要”“偏偏”，违背说话人意愿。 Must you talk in class? -How much do you earn? -Ill tell you if you must know it. 3. 一定，肯定 He must be crazy. He must have sta

13、yed up last night.4. 表推测的反应，反义疑问句中不能出现must的形式，反义形式取决于句中时态14 九月 2022201.He must be my English teacher,2. He must have finished his homework,3. It must have rained yesterday,isnt he?hasnt he?didnt it?e.g. I dont like this TV set. We must buy a new one. There was no more bus. They had to walk home.表示“必

14、须”这个意思时，must和haveto稍有区别。must着重说明主观看法，haveto强调客观需要。另外，haveto能用于更多时态。 need的用法一用作实义动词 need既可用于肯定句，也可用于否定句和疑问句(助动词是do或does). He needs your help. 肯定句He doesnt need your help.否定句Does he need your help?疑问句-Yes, he does.-No, he doesnt.1need sth. (名词，代词)1). We need a great deal of money now. 我们需要和多钱。 2). The

15、y dont it any more. 他们不再需要它了。 3). Does your father need any help? 你爸爸需要帮助吗? 2sth need doing (含被动的意义)= sth need to be done 例如： 1). The door needs painting. = The door needs to be painted. 那扇门需要油漆一下。 2). Your car needs mending. = Your car needs to be repaired. 你的车需要维修了。3need to do sth. 表示有义务或责任去做某事。如：

16、1). What do we need to take for the picnic? 野餐我们需要带些什么？ 2). Will we need to show our passports? 我们需要出示护照吗？ 3). You need to take good care of your mother. 你要好好照料你妈妈。 二用作情态动词 情态动词的主要特征：没有人称和数的变化。不能单独充当谓语。情态动词必须与一个实义动词一起构成复合谓语，并且这个实意动词要始终是动词原形。 变为否定句时只需在情态动词之后加not。 变为疑问句时只需将情态动词提到主语的前面。 二用作情态动词 need +

17、动词原型 (用于由if或whether引导的宾语从句中)1). I wonder if I need go to GZ again.我考虑是否要再去一次广州。2. need not + 动词原型 (否定句) 2). There is enough time. You neednt hurry. 有的是时间，你不必着急。 3. Need I wash the bowl? (用于疑问句)-Yes, you must. (肯定回答)-No, you neednt. (否定回答)1). Need I type this letter again? 我需要重新录入将这封信吗？ 2). -Must I h

18、and in my homework now? 现在我必须交作业吗？-Yes, you must. 对，你必须。-No, you neednt. 不，你不必。 三用作名词 need作为名词，含义为“缺乏，需要”；其复数表示“基本需要”。Its no need doing sth 做没用1). Theres no need for you to try again. 你不必再尝试了。2. in (great) need of（急需） 2). The factory is in great need of funds. 那家工厂急需资金。 = The factory is lack/short o

19、f funds. 3. meet the needs of(满足的需要)3). He had to work hard to meet the needs of his family. 他不得不努力工作来满足他家人的需要。注意对need问句的回答: -Need I finish the work today? -Yes, _. No, _. No, _.you mustyou needntyou dont have toneednt 对其它情态动词的回答: -Shall I tell John about it? -No, you _. -Must we do it now? -No, you

20、 _. neednt (dont have to) neednt(dont have to)Dare的含义dare (vt.)敢；敢做；激（某人做某事）；问（某人）有没有胆量（做某事） (vi.)敢；敢于；大胆；无畏于。(n.)激将，挑战。词的形式：过去式：dared过去分词:dared现在分词：daring第三人称单数：daresDare 做实意动词dare(vt.). 1敢；敢做；激（某人做某事）；问（某人）有没有胆量（做某事）dare用作实义动词，此时其后的动词不定式可带to也可不带to，且dare有人称和数以及时态的变化。(疑问句、否定句和条件句中, 可省略to )例句例如：1. I

21、dare to jump down from the top of the wall. （我敢从那墙头上跳下来。 )2.She does not dare (to) meet her teachers eyes.(她不敢与老师对视。） Dare 做情态动词2） dare用作情态动词，后跟动词原形，主要用于疑问句、否定句和条件句中。例句例如:1. How dare she do things like that to me? (她怎么敢对我做那种事? )- 2. Dare you catch the mouse? (你敢去抓那只老鼠吗？) -I darent do that. (我不敢抓。例句3

22、. If you dare say that to our teacher, I would vote for you. (如果你敢向我们的老师说那件事，我就投你一票。)14 九月 2022401.Being afraid of making mistakes ,he _ answer his teachers question A. doesnt dare B. doesnt dare to C. darent to D. not dare to 2.Having failed the exam. The little boy _go home and face his mom. A. da

23、res not to B. dares not C. dare not to D. dare not 14 九月 202241情态动词+have done (针对过去）should/ought to+have done用于肯定句时，表示“本该做某事而实际上没做”，用于否定句时，则表示“不该做的事反而做了”。1.You should have told him a week ago.你本来应该在一周前告诉他的。2.You ought not to have taken the magazine out of the reading room.他不该、把杂志带出阅览室的。must +have do

24、ne 表示对过去已经发生的行为进行推测，意为“想必/准是/一定作了某事”。1.It must have rained last night, for the road was very muddy. 昨晚 一定是下雨了， 因为地上很泥泞。2.We must have learned 2,000 words by the end of last term. 到上学期为止我们一定学了有两千个单词 。3.He must have gone to Beijing. 他一定已经去北京了。 could+have done,在肯定句中表示“本来能够而没能”，具有婉转的批评和责备之意。1. I could h

25、ave passed my exam easily, but I made too many stupid mistakes. 我本来能够轻易通过考试，但我犯了太多不该 犯的错误。2.You could have reported to me earlier. 你本该早点告诉我的。neednt +have done表示做了本来不必去做的事。1.She neednt have gone to the station yesterday.昨天她本不必到火车站去的.（昨天她去了）2.You neednt have bought it.你本可不必买它的。 （你买了）might/may）+have do

26、ne表示“本来可能”，但实际上没有发生的事。另外，还可表示“本来应该或可以做某事”之意，含有轻微的责备语气。1.You might not have told her.你本可以不告诉他的。（事实上你告诉他了）2. You might have come earlier.你本可以早点来的。（但没有这样）14 九月 202247 1 Children under 12 years of age in that country _ be under adult supervision when in a public library. (2004 上海） A. must B. may C. can

27、D. need直击高考14 九月 2022482 Some aspects of a pilots job_ be boring, and pilots often _ work at inconvenient hours. （2006 湖南） A. can；have to B. may；can C. have to; may D. ought to; must 14 九月 2022493The weather turned out to be fine yesterday. I _ the trouble to carry my umbrella with me. (2006 江西） A s

28、hould have taken B could have taken C neednt have taken D mustnt have taken14 九月 2022504 Hows your tour around the North Lake? Is it beautiful? It _ be, but it is now heavily polluted. （2007 全国I） A. will B. would C. should D. must 14 九月 2022515 I told your friend how to get to the hotel, but perhaps I have driven her there. （2007 陕西） A. c