大学英语 情态动词2.ppt

情态动词和助动词一样，都是辅助性的动 词，用来帮助构成不同的时态和语态，表示说话者的某种情态，没有人称和数的 变化may might can could shall should will would Must 无变化1. 表示请求Will you give her the letter?Would you please tell me your telephone number?2.表示习惯或倾向，与used to 进行对比Scarf used to be heavy smoker Father used not to be so forgetful2. Would强调过去某种特定情况下的动作 ，是完全过去的事情，与现在没有联系She used to get up at six in the morningShe would get up at six in the morningMan used to think that the earth was flatMan would think that the earth was flatIn those days, whenever I had difficulties, I____ Mr. Shen for help. A. Used to go to B. Was used to go to C. Would go to D. Used to going to He_____up at five, but now he gets up at six. A. Used to getting B. Would get C. Was used to get D. Used to get3.表示推测It will be Mr. Wang knocking at the door.It would be about ten o’clock when he left homeThey____in New York by now.A. will arrive B. will be arrivingC. will have arrived D. are arriving4. 表示命令、强迫All will arrive before 7:455. 表示意愿或者固执地坚持。

She won’t lend me the moneyThe window won’t open6.表示能力（拟人化）The hall will seat 1000 people7.表示客观事实Fish will die out of water8.表示意图或允诺You wii have your share9Would ratherWould rather(sooner)….thanHe would rather___than____the secret.A. die…telling B. die…to tellC. dead….tell D. die…tellI would rather you _____her the bike the other day.A. didn’t lend B. hadn’t lentC. should not lend D. wouldn’t have lent1）表示许可You can borrow two books at a time from the library2）表示可能性I can’t guess whose book it is3）表示能力She couldn’t climb the mountain注意：Can’t help和couldn’t bear中的不能变成be able to.The weather was able to clear upThe fire was not able to be put outCan(could)+have+过去分词有时等于 may(might)+have+过去分词意思为可能Can they have missed the trainHe couldn’t have been swimming all dayShe couldn’t have heard you knocking at the doorHave to 和 must1)have to 强调客观需要，must强调主观看 法I must learn another languageI have to learn another languageSomeone must have lost the game.Someone had to lose the game注意以下两句Though she didn’t need to , she must go.You don’t have to come again, but you must2.have to 表示义务或习惯动作，must表示 重要或急迫的事情。

We have to care for the youngShe has to be at the office before eight every day.You must go to the manager at once, or you’ll be dismissed.3) have to 可用于不同时态，must一般只 用于现在时I have to leave nowWe’ll have to buy another TV setThey had to put off the sports meet because of the bad weather4.must可以表示推测，have to 不能This must be Jim's penThere must be something wrong with the machine注意:Have to 的否定式和疑问式可以按照助动词 的变化规则构成，也可以按照通用变化规 则Have you to finish the work before supper?Do you have to finish the work before supperMust need 和 need notMust not 表示禁止, 所以在回答must 引导 的问题时，如果否定，该怎么回答？Must needs 和needs mustNeeds为副词,相当于necessarily, of necessity二者均可表示必须，必定，不得不，但 must needs 还可以表示偏偏，偏要。

I must needs go there nowNeeds must when the devil drives.She must needs go away when I want her.Need可以做助动词，也可以做行为动词Father sent me the book, so I didn’t need to write to him for it.Father sent me the book, so I needn’t have written to him for it. She didn’t need to comeShe needn’t have come注意:作助动词用，need只用于疑问句和否 定句，肯定句中用must, have to, should, ought to等Need you do it right now? I needn’t, but he must.Ought to没有词性变化，通用于所有人称 和时态He knew he____ tell her that.A. ought not B. ought to notC. didn’t ought to D. ought not toOught to表示义务或责任，提醒某人义务 或提出劝告，指出一个正确、明智的行为 。

Must强调主观愿望，涉及说话人的权威Have to表示由某种情况或环境所迫而不得 不做的事Should和ought to完全相同，但ought to语 气更重You ought to respect the oldYou must do it at onceWe’ll have to reconsider the matterWe should (ought to) do more for the country1.表示征求意见或请求指示Shall we meet in the evening?How shall I start the machine?2.表示意图、意志、允诺或命令等，但shall所表 示的意志是说话人的意志，并非句子主语的意志I shall give you a lot of moneyEach citizen shall carry his identification card when travelling.She shall get this paper in the eveningHe shall get what he deserves1. 用于疑问句或感叹句，表示“推断”How should I know?Why should you be worrying?2. 用在I’m surprised, it worries me, it’s a pity, it’s unthinkable等结构后面的句子中表 示惊讶、忧虑、惋惜、欢欣等情绪。

I’m surprised that he should eat so little every day.It’s a pity that she should fail in the entrance examination.。