18-19Unit2SectionⅢGrammar——情态动词Ⅱ

1、Section 山 Grammar情态动词（n）第6页语境自主领悟先观察原句后自主感悟 By now his restaura nt ought to be full of people. Does your father need any help? What do we need to take for the picnic? There is eno ugh time.Youneedn't hurry. His mother is ill.He has tostay at home to look after her. Something terrible must have h

2、appe ned if Li Chang was not coming to eat in his restaura nt as he always did.1. 以上句子中，句中的黑体 词都是情态动词，而句中的黑体 词是实义动词。2. 以上各句中的情态动词后都接动 词原形。其中句中must have happened的意思是一疋已经发生 了”。3. 上述句子中ought to意为 应该 ；need意为需要 ；has to意 为“不得不”。语法精要点拨一、ought to的用法1“应该”，表示责任或义务。用于表示按道理应当，常指客观的义务或 责任，大多数情况下可用should代替，但比shou

3、ld语气重。You ought to study harder tha n your brother.你应该比你哥哥更努力学习。I shouldhelp her because she is in trouble.她有困难了，我应该帮助她。2. “应该”，表示劝告、建议或命令。 should和ought to可通用，但在疑问句中常用 should。ought to 的否定式为 ought n't to 或 ought not to。You ought to bala nee career and family.你应该平衡好事业与家庭之间的关系。Should I ope n the wi

4、n dow?我可以打开窗户吗？3. “应该”，表示推测。可与should换用。Mary ought to be here soon.玛丽应该很快就来了。This is where the oil ought to/shouldbe.这里应该就是石油存在的地方。即时训练1用ought to补全句子 下次过马路时，你应该更小心些。You ought to be more careful when you cross the road next time. 你不该责备他。You oughtn't/ought not to scold him. 一一我应该明天动身吗？是的，你应该。Ought

5、I to leave tomorrow?Yes, you ought to.二、have to的用法have to意为“不得不”，有时态、人称和数的变化，其否定形式和疑问形 式需要借助于助动词do。It was raining outside； we had to stay at home.外面下雨了，我们不得不待在家里。考点警示have to, must(1)两者都可意为“必须，应该”，但have to表示客观的需要，而must表示 说话人主观上的看法，即主观上的必要。have to有人称、数和时态的变化，而 must只有一种形式。He had to look after his siste

6、r yesterday.昨天他不得不照顾他的妹妹。(3) 在否定结构中，don't have to表示“不必”；must n't表示“禁止，不许”。You don't have to tell him about it.你不必把此事告诉他。(4) 在回答must的一般疑问句时，肯定式常用 must,表示“必须”，否定式 常用 need not(needn't或 don't have to, 表示“不必”。即时训练2完成句子(每空1词) 他没有钱，只好放弃这个计划。He had no money so he had to give up this plan

7、. 你千万不能告诉他这个秘密。You mustn't tell him the secret.(3)我们必须今天下午交作业吗？不，你不必。Must we hand in our homework this after noon?No，you do n't have jo.三、need的用法(1) need作情态动词时，后跟动词原形，表示“需要，有必要”，无人称和 数的变化，多用于否定句、疑问句或条件句中。You need n't go there noW尔不必现在去那儿。Need I go there now?我现在需要去那儿吗？考点警示由need引导的一般疑问句的肯定

8、回答常用 must或have to,否 定回答常用needn'。Need I hand in my paper now?Yes, you must./No，you needn't.我现在需要交上论文吗？是的，你必须。/不，你不需要。(2) 作为实义动词，同其他实义动词一样，可用于各种句式，有时态、人称和数的变化，构成否定句和疑问句时要借助于助动词do。You n eed to be careful.你得小心些。You don't n eed to be so worried.你不必如此担心。名师点津当need作实义动词“需要”讲时，其后跟不定式的被动形式， 相当于跟v.

9、-ing的主动形式，在这一点上，与want和require作“需要”讲时用 法一样。The house n eeds/wa nts/requires repairi ng/to be repaired.这所房子需要修葺。即时训练3完成句子 我的房间很乱，但今晚出去之前我不需要打扫，我会早晨打扫的。My room is in a mess， but I needn't clean it before I go out tonight.l can do it in the morni ng. 一一我需要留下来帮他们吗？是的，你必须留下来。不，你不必。Need I stay to help

10、them?Yes, you must. /No，you needn't.四、情态动词+ have done“情态动词+ have don6表示对过去事情的推测。各情态动词的这种具体用 法如下表：can /could have done1.过去可能（表推测）2 .本能做而未做（表虚拟）should/ought to have done本该做而未做may/might have done1. 过去也许做了（表推测）2. 本可能做而未做（表虚拟）must have done一定已经做了n eed n't have done本不必做而做了From what you said, she m

11、ust have toldyou all about it.从你所说的来看，她一定把一切都告诉你了。You should have toldme earlier or I might have gonewith them .你应该早点告 诉我，不然的话我就会和他们一块去了。They could have sent upthe satellite successfully.他们本来有能力成功发射这颗卫星的。You ought to/should have beeimore careful.你本应该更小心一些的。You needn't have toldthem about it.你本来没

12、有必要告诉他们那件事。即时训练4完成句子 我从未玩得更开心过这是完美的一天。I could n't have enjoyed myself more it was a perfect day. 他们本应该在午饭时间就到达的，但是他们的航班被耽搁了。They should have arrived at lunchtime but their flight was delayed.【导学号：65162019】 迈克本来不必那么匆忙的。全速驾驶之后，他早半个小时到达了。Mike needn't have hurried. After driving at top speed , h

13、e arrived half an hour early.语法应用落实I 用适当的情态动词填空1. You ought to/should have given(give) him some advice.He was too upset at that time.2. You mustn't smoke(smoke) in this part of thehospital.3. There was ple nty of time.She n eed n't have hurried(hurry)4.1 have no bike, so I have to go(go) to

14、the office on foot.5. You needn't buy(not buy) a gift, but you can if you want to.6. Look! The road is wet.It must have rain ed(rai n) last ni ght.7. Bob ought not to speak (not speak) to his mother like that.8. You must come(come) here on time or you'll be fined next time.9. Hurry up! We ou

15、ght to/should go(go) to school right away.10. Her eyes are red.She must have been(be) crying.n .完成句子1. I have just found that I have to attend an important class meetin我必须参力廿 一个重要的班会)that afternoon.2. The length of the article should be limited to 400 words or so应当限制在 400 词左右).3. The last important

16、thing you should remember(你应当记住的是 )is that you have to send the article to me before June 28.4. George can't have gone不可能走)too far.His coffee is still warm.5. I love the weekend, because I needn't get up early 不必早起）on Saturdays and Sun days.6. Why did n't you tell me about your trouble last week ? If you had told me , I could have helped就可能帮你了 ）.7. Sorry, Mum ! I failed the job in terview aga in.Oh, it's too bad.You should have made fullpreparations本应该做充足的准备）.8.1 needn't h