新课标高一英语必修三精品课件 Unit 2 Healthy eating Grammar(14张)

文档属性

名称 新课标高一英语必修三精品课件 Unit 2 Healthy eating Grammar(14张)
格式 zip
文件大小 108.3KB
资源类型 教案
版本资源 人教版(新课程标准)
科目 英语
更新时间 2017-05-23 18:24:05

图片预览

文档简介

课件14张PPT。新课标高一
英语必修3Unit 2 Healthy eatingGrammar1should 和ought to1. should和ought to表示责任、建议或劝告,翻译为“应该”,后者语气强一些,可用于各种人称。 You should listen to the doctor’s advice if you want to recover soon. Such things ought not to be allowed. 12. should接动词的完成式,是一种谴责,表示过去应该做而没有做或过去做了而不应该做。 I missed the class. I should have come earlier. 1I shouldn’t have made such a foolish mistake.3. 表示要求,命令时,语气由 should(应该)、had better最好)、must(必须)渐强。1have to和must1. 两词都是“必须”的意思,have to 表示客观的需要, must 表示说话人主观上的看法,既主观上的必要。My brother was very ill, so I had to call the doctor in the middle of the night. (客观上需要做这件事)He said that they must work hard.(主观上要做这件事) 12. have to有人称、数、时态的变化,而must只有一种形式。但must 可用于间接引语中表示过去的必要或义务。He had to look after his sister yesterday.13. 在否定结构中: don't have to  表示“不必”; mustn't 表示“禁止”You don't have to tell him about it. You mustn't tell him about it.   1need和have to1. need表示需要,主要用于否定句和疑问句。用于疑问句,肯定回答用must,否定回答用needn’t have to表示他人或客观情况要求"必须",也可以翻译为"不得不",have to否定形式意思是"不一定"或"没有必要"。 You needn’t come if you don’t want to. 1I don’t think you need be so polite to her. You don’t have to work so hard if you just want to pass Band 4. Because of the heavy rain, the children have had to get up earlier than usual this week. 12. need后面接动词的完成式,主要用于否定句,表示本可不必做某事。 “needn’t +不定式完成式”表示“本来不必做,但实际做了”。didn’t need to do表示: 过去不必做某事, 事实上也没做。 Needn’t have done表示: 过去不必做某事, 但事实上做了。 注: 1John went to the station with the car to meet Mary, so she needn’t have walked back home. There was plenty of time. She __________.
mustn’t have hurried
B. couldn’t have hurried  
C. must not hurry
D. needn’t have hurried 1needn’t have done. 意为“本不必”,即已经做了某事,而时实际上不必要。
Mustn’t have done 用法不正确,对过去发生的事情进行否定性推断应为couldn’t have done, “不可能已经”。 must not do 不可以(用于一般现在时)。1