新编英语教程第三版BOOK2 Unit 3

Unit 3
3. He may / might have gone without you.
may / might / can / could + have done indicating “speculations about past actions”表示对过去事情可能性的推测
can + have done 表示可能性的猜测时，只能用于疑问句中
① I intend to go skating with you yesterday but I couldn’t because my mother didn’t let me. I would have liked to go skating with you yesterday, but my mother didn’t let me. ② I meant to sit in on Prof. Xin’s class this morning but I didn’t because I had an important meeting to attend. I would have liked to sit in on Prof. Xin’s class this morning, but I had an important meeting to attend.
B: Why don’t you use my bike? You might as well. (or You
may / might as well use my bike. The last bus might have gone)
Dialogue I
Pollution Control
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the public library. It’s about a quarter to nine now.
B: He may / might have gone without you. A: Maybe, but he ought to have told me so.
Language Structure
Language Structure
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Practice 1
A: Everybody signed up for the sports meeting, but I didn’t see your name. B: I didn’t sign up.
A: Wh百度文库 not?
B: I would have liked to, but I sprained my ankle.
Think it
How many kinds of pollution are there nowadays?
What causes these pollution? What bad influences
does pollution have on our life?
Unit 3
Air Pollution
e.g. It’s very dark outside. You may / might as well take a torch along.
When may / might as well + do used with the first person pronoun, it expresses “intention” in an unemphatic way. e.g. The film is at six. I might as well have my supper after the film.
A: She learnt all the dialogues in the textbook by heart,
though. B: But that’s no use. As a matter of fact, she needn’t have done that.
Language Structure
Unit 3
Practice 4
A: Is Liu in the gym? B: No, I don’t think so. A: Can / Could she have gone to the library?
B: No, she can’t / couldn’t have gone there. I just saw her
Language Structure
Look at the following sentences and pay attention to the grammar rules they use:
Unit 3
1. I would have liked to sign up, but I sprained my ankle. 2. She should / ought to have had more oral practice during the term.
going out with a tape in her hand. A: In that case, she must have gone to the language lab.
Language Structure
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Practice 5
A: It’s getting very late. I must be off. B: Oh, I didn’t realize it was so late. A: I hope I’ll be able to catch the last bus home.
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2. She should / ought to have had more oral practice during the term. should / ought to + have done expressing “unfulfilled obligation” 应该做的事情没有做，表示一种责备的口气。 shouldn’t / oughtn’t to + have done 否定式表示某种行为不该 发生却发生了，表示一种责备的口气 Use the structure to make sentence following the given cues. ① The exhibition was a good one. All of us visited it except John. John should / ought to have come with us.
may / might / could + have done 既可用于陈述句，也可用于疑 问句中
e.g. She may / might / could + have gone to the library.
Can she have gone to the library?
Could she have gone to the library?
Language Structure
Unit 3
Practice 2
A: Mary failed in her oral English test again. B: She should / ought to have had more oral practice all through the term
② They bought a book for Mary but she didn’t like it. They oughtn’t to / shouldn’t have bought the book for Mary.
Unit 3
She needn’t have learned all the dialogues by heart. needn’t + have done expressing “unnecessary past actions” 已经做过的但无必要做的行为 Use the structure to make sentence following the given cues. ① I wrote a summary in more than five hundred words. But the teacher only asked for 200 words. I needn’t have written such a long summary. ② Mary went to the station an hour before the train started. Mary needn’t have gone to the station so early.
e.g. Where is my mobile phone? It was here a moment ago. It couldn’t have been stolen last night.
She must have gone to the language lab. must + have done indicating “affirmative deduction about past actions”对过去事情非常肯定的推测 e.g. Tim looks tired. He must have stayed up late last night.
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5. You may / might as well use my bike. may / might as well + do used with the second or third person pronoun expressing “suggestions” 建议或劝说某人采取某种行动，有时相当于had better.
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Practice 3
A: I wonder where Zhang can be. B: Did you have an appointment with him? A: Yes. He said he’d meet me at half past eight and take me to
Water Pollution
Unit 3
Unit 3
Noise Pollution
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Land Pollution
Dialogue
Pollution Control
Unit 3
Questions
Browse through the text, try to answer following questions. 1. Why is London no longer a city full of fog? 2. What is the cause of air and water pollution in the city where the speaker A lives? 3. What problem do cars bring? 4. What should be done to bring pollution completely under control?
She needn’t have learned all the dialogues by heart.
3. He may / might have gone without you.
4. She can’t / couldn’t have gone to the library.
She must have gone to the language lab. 5. You may / might as well use my bike.
May / Might she have gone to the library?
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4. She can’t / couldn’t have gone to the library. can / could not + have done indicating “negative deduction about past actions”对过去事情否定的推断
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1. I would have liked to sign up, but I sprained my ankle. would have liked to expressing “unfulfilled wish” 想要做的事情没有做成
Use the structure to make sentence following the given cues.