情態(tài)動詞和虛擬語氣 -By Bring English can, could may, might will, would shall, shouldmust, need have to, ought tocant, may not mustnt, needntdont have to shouldnt, shantbe able to dare情 態(tài) 動 詞1. can, could表示能力He can speak English very well.He could draw very well when he was five.表示許可You can use my computer now.You cant eat in class.表示請求Can you tell me the way to the post office?Could you show me the way to the Beihai Park?表示猜測Generally, she is a quiet girl. But sometimes she can be talkable.Someone is knocking at the door. Who can it be? It cant be Mr. Zhang. He has gone abroad.The hunters have been lost for days. They could starve.表示驚訝How can she be late for class? She is always on time.2. may, might請求許可May I have a look at your new mobile phone?表示可能The man over there may be your new teacher.He might come here by train or by air.3. will, would表示意愿、傾向On rainy days, she will sit by the window and watch the rain for hours.He was poor, but he would dress up as a rich man.表示請求Will you please give your seat to the old lady?Would you like to join us for dinner?4. shall用于第一人稱，表示將要I shall go with you next time.用于第一人稱，表示征求意見Shall I put the book back on the shelf?/Shall we go out for a walk?用于第二、三人稱，表示許諾、義務、規(guī)定、威脅You shall get a new mobile phone if you pass the exam.Everyone shall wait in line when they buy tickets.According to the agreement, the interest shall be divided equally among the three investors.5. should表示建議（應該）You should lie down and have a rest.表示猜測Its seven oclock. Mr. Li should be there.You have practiced a lot. You shouldnt have any trouble in passing the test.表示驚訝Its surprising that such a pretty girl should be a thief.6. must表示必需We must finish our work by noon.表示猜測There must be something wrong .表示責怪（偏偏，非得）Tom, must you play the piano at this time?My car must break down when I was hurrying to work.7. need表示需要（否定或疑問句）You neednt go to school today.用作實意動詞You dont need to go to school today.8. have to表示必需，不得不You have to finish your work by noon.9. ought to表示應該You ought to hand in your homework before school is over.10. dare表示 敢How dare you say that to your mother?She darent go out in the dark.He dared not ask the teacher for help.用作實意動詞He dares to swim across the river by himself.Does he dare to swim across the river by himself?He doesnt dare to swim in the river.注意各種否定式：1. cant I cant play any musical instrument.(不能)It cant be possible. Its so rediculous！(不可能)2. mustntYou mustnt smoke in public places.(千萬別)3. may notThat may not be true.(可能不)4. neednt (沒必要)5. dont have to (沒必要)6. shouldnt (不應該)情態(tài)動詞+HAVE DONE1. must have done 一定做過某事2. may/might/could (not) have done 可能(沒)做過某事3. cant have done 不可能做過某事4. should(not) have done 本(不)應該做某事5. neednt have done 本沒必要做某事6. ought(not) to have done 本(不)應該做某事7. would(not) have done 本(不)會做某事虛擬語氣一. 在條件句中的用法if 從句動詞從句動詞主句動詞主句動詞與現(xiàn)在事實相反過去時（be用were）would/should/could/might+動詞原形與過去事實相反過去完成時（had done）would/should/could/might+have done與將來事實相反1.過去時（be 用were）2. should+do3. were + to dowould/should/could/might+動詞原形1. If I were you, I would ask the teacher for advice. If he knew the truth, he would tell you.2. If you had come earlier, you would have met the famous star. She wouldnt have been so angry if you had apologized to her.3. If it were to snow this evening, they would /should /could/might not go out. If it should break down within one year, we would repair it at our expense. If you went there, I would /should/could/might go with you.需要注意的問題1. 錯綜條件句 If you had followed my advice, you would do it better now. If I were you, I wouldnt have missed the film last night.2. 倒裝句（省略if） Were she older, she would do it. Should he come, tell him to ring me up. Had we taken the taxi, we wouldnt have been late for the meeting.二. 介詞短語等代替條件從句 Without air, there would be no living things. But for your help, we wouldnt have finished the task on time.三. 根據上下文判定1. I would have come to your party, but I was too busy last night.2. I was too busy last night, otherwise I would have come to your party.3. You were driving too carelessly, otherwise you wouldnt be in hospital now.四. 在其他從句中的 虛擬語氣1. I wish I had my own company. I wish I would travel in space some day. I wish I had known you earlier.2. I would rather you came here tomorrow. I would rather I hadnt seen the film.3. He talks as if he knew everything. He talks as if he had been to the moon.4. He suggested/ordered/requested. that. (should) do.5. It is important/strange/necessary that . (should) do.6. It is commanded/suggested/required that. (should) do.7. The requirement is that. (should) do.8. We all agreed to the suggestion/request/adviece that.(should) do .