牛津译林版八年级英语上册《Wild animals》PPT课件(第4课时)，共16页。
May I help you sir?
一、情态动词may的用法
1. 用情态动词may 表示肯定推测，译为“可能，也许”，通常只用于肯定句与否定句中，相当于perhaps, possibly 或maybe。
may not :可能不，表示否定推测
eg：The news may or may not be true.
这消息也许是真的，也许不是真的.
2. may 除了可以表示推测，还可以表示请求，许可，允许，通常用于疑问句中。
eg：—May I go now? 我现在可以走了吗？
—Yes, you can. / No, you can't.
回答时不可用may, might,或could及其否定形式
3. 表示必须，必要。must 和have to
在陈述句中，must强调说话者的主观想法， have to强调客观需要，意为“不得不”。
在疑问句中，回答must引出的问句时，肯定回答用must, 否定回答可以用needn't或don't have to(不必)，一定不能使用mustn't(禁止，不准)。
eg：—Must I finish my homework now ?
我现在一定要完成作业吗？
—Yes, you must. / No, you needn't/don't have to.
是的，一定要。/不，没必要。
二、动词不定式结构
1. eg：Linda wanted to visit the park.
Sandy needs to go with them.
Millie decided to stay at home.
上面例子中主要行为动词后面的动词都采用了“to ＋ 动词原形”的结构，我们把这种结构称为动词不定式(有时可以不带to)。动词不定式没有人称和数的变化，在句子中不能单独作谓语。
2. 也有一些动词后面可以跟动名词结构doing sth. , 但是 意义不同。
forget to do sth. 忘记去做某事(事情未做)
eg：Don't forget to lock the door when you go out.
当你出去时别忘了锁门。
forget doing sth. 忘记做过某事(事情已做)
eg：I forgot washing hands and washed again.
我忘了已经洗过手了，又洗了一遍。
课堂练习
用所给词的适当形式完成句子
1．—Must I finish my homework now?
—No, you needn't. You may ________ (finish) it this afternoon.
2．She agreed_________(let) me go early.
3．The students prepare _________ (play) football after class this afternoon.
4．She planned __________ (visit) our city this summer.
5．Why did you choose _________(sit) in the front of the coach?
6．I want ________ (go) to the library this afternoon.
7．We hope __________(arrive) around six.
8．It's raining hard so I decide ___________ (not go) out.
9．The policeman told the children _____________ (not play) football in the street.
10．Please ask him _____________ (not watch) TV until he finishes his homework.
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关键词：《Wild animals》PPT课件免费下载，.PPT格式
