MUGrammar课件.pptVIP

4. 情态动词+have done结构 作用（1）推测过去 （2）虚拟 1.must have done: 1.The lights went out. They must have left the office. 2.It must have rained last night, for the road was quite muddy. 2. could have done 1.Mary met Jack at the airport yesterday afternoon, so she _____________________ (attend) your lecture. 2.You _______________ (do)it better，but you were too careless. 3. might have done 1. She hasn’t come back. She might have been eaten by the tiger. 2.She was lucky enough. The tiger might have eaten her. 4.should /ought to have done 1.You________________ the meeting earlier 2.You _______________her the truth. 5.needn’t have done We__________________ a taxi here，for it was very near to the school 注意：didn’t need to do： I didn’t need to clean the windows. My brother did it . must have done could/might have done (2) should/ ought to have done needn’t have done 2. could have done 1.Mary met Jack at the airport yesterday afternoon, so she _____________________ your lecture. 2.You _______________ it better，but you were too careless. 3. might have done 1. She hasn’t come back. She might have been eaten by the tiger. 2.She was lucky enough. The tiger might have eaten her. * * 人教课标 高一 必修 3 Unit 2 a. should, ought to 都可表示劝告、建议或命令译为“应该”。大多数情况下可替换，但比 should 语气重。在疑问句中常用should。ought to 的否定式为 oughtn’t to 或 ought not to。 You should / ought to go to class right away. Should I open the window? What should we do next? 1. should/ ought to b. should/ought to 表推测，指 “按道理应该” -When can I come for the computer? -It should / ought to be repaired by next Monday afternoon. 2. must 和 have to 　must 的用法? 1) must 的肯定形式表示“必须”，否定式mustn’t表示“禁止、不许”。 You must come here. You mustn’t take the book away from the library. 2）由 must 引起的疑问句，肯定回答要用 must 或 have?to,?否定回答要用needn’t 或 don’t?have?to,?意思是“不必” ；如：? — Must?I?finish?the?task?right?now?? 我现在必须完成这个工作吗？ — Yes,?you?must.?/?Yes,?you?have?to.? 是的。 (— No, you needn’t. / No, you don’t