Lecture 3 情态动词.pptVIP

情态动词 2.1 情态动词的语法特征 2.2 must表示推测 2.3 表示推测的用法 2.4 情态动词+ have +过去分词 2.5 would rather表示宁愿 2.1 情态动词的语法特征 1） 情态动词表示期待或估计某事的发生。 2） 情态动词 后面只能接动词原形 3） 情态动词没有人称，数的变化 4） 情态动词没有不定式，分词，等形式。 2.2 must表示推测 must用在肯定句中表示较有把握的推测，意为一定。 1) must be（对现在情况的推测判断） You have worked hard all day. You must be tired.　 He must be working in his office. 比较： 　　　He must be staying there.　　　　He must stay there. 　 2) must have done对已发生的事情的推测时 I didnt hear the phone. I must have been asleep.　 3) must have been doing 对过去某时正发生的事情的推测 ---Why didnt you answer my phone call? ---Well, I must have been sleeping, so I didnt hear it. 4) 否定推测用can‘t。If Tom didn’t leave here until five o‘clock, he can’t be home yet.　 如果汤姆五点才离开这儿，他此时一定还未到家。 幻灯片 2 ?2.3 情态动词表示推测的用法 1）情态动词+动词原形。表对现在或将来的情况的推测 　I don‘t know where she is, she may be in Wuhan. 2）情态动词+动词现在进行时。　对现在或将来正在进行的情况进行推测。At this moment, our teacher must be correcting our exam papers.这时，我们老师想必在批改试卷。 3）情态动词+动词完成时。 对过去情况的推测。 We would have finished this work by the end of next December. 明年十二月底前我们很可能已完成这项工作了。 The road is wet. It must have rained last night. 地是湿的，昨天晚上一定下雨了。 4）情态动词+动词的现在完成进行时。对过去正在发生事情的推测。 Your mother must have been looking for you你妈妈一定一直在找你。 5）推测的否定形式，疑问形式用can‘t, couldn’t表示。 Mike cant have found his car, for he came to work by bus this morning. 迈克一定还没有找回他的车，因为早上他是坐公共汽车来上班的。 　注意：could, might表示推测时不表示时态，其推测的程度不如can, may。 幻灯片 2 2.4 情态动词+ have +过去分词 may(might) have + done sth, can (could) have + done sth　表示过去，推测过去时间里可能发生的事情。 Philip may (might) have been hurt seriously in the car accident. Philip can (could) have been hurt seriously in the car accident. 2)　must have +done sth，对过去时间里可能发生的事情的推测，语气较强，具有“肯定”，“谅必”的意思。 ---Linda has gone to work, but her bicycle is still here. ---She must have gone by bus. 3) couldn’t have +done sth，对过去时间里可能发生的事情的推测，语气较强，具有“不可能”，“一定没有”的意思。  4) ought to have done sth, should have done sth　　本应该做某事，而事实上并没有做。否定句表示不该做某事而做了“ You ought to (should) have been more careful in this experiment. He ought not to have thrown the