2018-2019学年高中英语外研版必修四课件：Module 6 Section Ⅲ Grammar

Module 6 Unexplained Mysteries of the NaⅢ Grammar——情态动词
＋have done的用法
[语 境 自 主 领 悟]
先观察原句 后自主感悟 ①Many people think the monster may be a distant cousin of 1.①②句表示可能性的推测， 意为“可能， the Loch Ness monster in Scotland. 也许”。 ②They also think that there might be similar creatures in other 2．③④句表示对过去发生的事情的推测， lakes around the world. 意为“可能已经”。 ③But in China， the idea of the dragon may have come from the 3．⑤句表示对过去事情的很有把握的肯 alligator. 定推测，意为“肯定做过某事”，而⑥句 ④You might have given your parents more help earlier. 则表示对过去发生事情的有把握的否定 ⑤It must have rained last night， for the road was quite muddy. 推测，意为“不可能做过某事”。 ⑥He can't have forgotten it，for he talked about it yesterday. 4 ．⑦句表示“过去本应该做却未做的 ⑦You ought to/should have done the job more carefully. 事”，⑧句则表示“过去本不该发生却发 ⑧ You oughtn't to/shouldn't have asked such a foolish 生了的事”。 question.
[名师点津] 含有 must have done 结构的反意疑问句中，若有表示过去的时间状语， 反意疑问部分用“didn't＋主语？”；若没有表示过去的时间状语，反意疑问 部分则用“haven't/hasn't＋主语？”。 They must have gone there last night，didn't they? 他们昨晚一定是去那里了，不是吗？ They must have been to the Great Wall， haven't they？他们一定去过长城， 不是吗？
3．can/could have done sth.是对过去的推测，表示“可能做过某事”，主 要用于否定句和疑问句中。 could 语气较委婉， 肯定句中一般用 could 不用 can。 Mr.Smith can't have gone to Beijing，for I saw him in the library just now. 史密斯先生不可能去北京了，我刚才还在图书馆见过他。 — Where can they have gone? — They could have gone to the cinema. ——他们能去哪里呢？ ——他们可能去电影院了。
[语 法 精 要 点 拨]
1．may/might have done sth.表示对过去行为的推测，意为“也许/或许已 经做过某事”，might 可能性更小，主要用于肯定句和否定句中。 John isn't at home.I think he may/might have gone to school. 约翰不在家，我想他可能去上学了吧。 You might have read about it in the papers. 你可能已经在报纸上看到这个消息了。
[名师点津] could have done sth.还可表示过去本可以完成而实际上未完成的动作。 You could have done better，but you were too careless. 你本来可以做得更好，但你太粗心了。
[即时训练 1] 用适当的情态动词填空 ①George can't have gone too far.His coffee is still warm. ②—We are very worried about Tom.Why hasn't he come back? —Don't worry.He may/might have been caught in a traffic jam. 【导学号：12112041】 ③—How did you do in the test? —Not so well.I could have done much better but I misread the directions. ④The streets are wet.It must have rained last night.
4．ought to/should have done 表示过去本来应该做某事(而实际上并没有 做)， 意为“理应做„„， 本来应该做„„”， 常表示遗憾； ought not to/shouldn't have done 表示“过去本来不应该做某事(而实际上做了)”，含有指责对方或 自责的意味。 The flowers have died.I should have watered them often.这些花儿都死了。 我本来应该常给它们浇水的。(其实没浇水，表示遗憾) You ought not to have told them the truth. 你本不应该告诉他们真相的。(其实你告诉他们了，含有责备的意味)
[名师点津] might have done 有时表示 “本来可以做的事而实际上没有做”，含有 “劝告，责备”的语气。 You might have been more careful. 你本来可以多加小心的。
2．must have done sth.表示对过去发生的事或行为的肯定推测，意为“一 定做过某事” ，只用于肯定句中。 He reasoned that since she had not answered his letter she must have left here.他推断，由于她没有给他回信，她一定是已经离开这里了。