1、Unit 2 Healthy eatingSection Grammar情态动词()语 境 自 主 领 悟先观察原句后自主感悟By now his restaurant ought to be full of people.Does your father need any help？What do we need to take for the picnic？There is enough time.You neednt hurry.His mother is ill.He has to stay at home to look after her.Something terrible mu
2、st have happened if Li Chang was not coming to eat in his restaurant 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“一定已经发生了”。3.上述句子中ought to意为“应该”；need意为“需要”；has to意为“不得不”。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should语气重。
3、You ought to study harder than your brother.你应该比你哥哥更努力学习。I should help 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oughtnt to或ought not to。You ought to balance career and family.你应该平衡好事业与家庭之间的关系。Should I open the window?我可以打开窗户吗？3“应该”，表示
4、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/should be.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 oughtnt/ought not to scold him.我应该明天动身吗？是的，你应该。Ought I to leave tomorrow?Yes，you ought
5、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。名师点津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。(2)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 sister yesterday.昨天他不得不照顾他的妹妹。(3)在否定结构中，do
6、nt have to表示“不必”；mustnt表示“禁止，不许”。You dont 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(neednt)或dont have to，表示“不必”。即时训练2完成句子他没有钱，只好放弃这个计划。He had no money，so he had to give up this plan.你千万不能告诉他这个秘密。You mustnt tell him the secret.我们必须今天下午交作业吗？不，你不必。Must we hand
7、 in our homework this afternoon?No，you dont have to.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 neednt go there now.你不必现在去那儿。Need I go there now？我现在需要去那儿吗？名师点津由need引导的一般疑问句的肯定回答常用must或have to，否定回答常用neednt。Need I hand in my paper now?Yes，you must./No，you neednt.我现在需要交上论文吗？是的
8、，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 need to be careful.你得小心些。You dont need 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.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 needs/wants/requires repairing/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
9、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 neednt clean it before I go out tonight.I can do it in the morning.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 them?Yes，you must./No，you neednt.四、情态动词have done“情态动词have done”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.过去可能做了(表推测)2.本能做而未做(表虚拟
10、)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neednt have done本不必做而做了From what you said，she must have told you all about it.从你所说的来看，她一定把一切都告诉你了。You should have told me earlier or I might have gone with 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 s
11、ent up the satellite successfully.他们本来有能力成功发射这颗卫星的。You ought to/should have been more careful.你本应该更小心一些的。You neednt have told them about it.你本来没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 couldnt have enjoyed myself moreit 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
12、 but their flight was delayed.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 neednt have hurried.After driving at top speed，he arrived half an hour early.用适当的情态动词填空1You ought to/should have given(give) him some advice.He was too upset at that time.2You mustnt smoke(smoke) in this part of the hospital.3There was
13、plenty of time.She neednt have hurried(hurry)4I have no bike，so I have to go(go) to the office on foot.5You neednt buy(not buy) a gift，but you can if you want to.6Look! The road is wet.It must have rained(rain) last night.7Bob ought not to speak(not speak) to his mother like that.8You must come(come
14、) here on time，or youll be fined next time.9Hurry up! We ought to/should go(go) to school right away.10Her eyes are red.She must have been(be) crying.完成句子1I have just found that I have to attend an important class meeting(我必须参加一个重要的班会) that afternoon.2The length of the article should be limited to 400 words or so(应当限制在400词左右)3George cant have gone (不可能走) too far.His coffee is still warm.4I love the weekend，because I neednt get up early (不必早起)on Saturdays and Sundays.5I neednt have worried (本没有必要担心)before I came to the new school，for my classmates here are very friendly to me.