巧记must,can,may表示“推测”的用法

1、巧记 must, can, may 表示" 推测”的用法首先请看下面的顺口溜：can不肯，may不问，must肯定不否问。这个顺口溜介绍了 can (could), may (might), must表" 推测”时所适用 的句式的区别。其含义如下：can不肯，即：can (could)般不用于肯定句；may不问，即：may (might)殳 不用 于疑问句 ;must 肯定不否问， B|J ：must 一般仅用于肯定句，不用于否定句和疑问 句。一、表示有把握的推测时，肯定句用 must (定，准是 )，否定句用 can' t (不 可 能，一定不 )。 must (

2、can* t) + 动词原形，表示对现在情况的推测。 must (can ? t) + be doing, 表示对现在正在进行的情况的推测。 must (can' t) + have done, 表 示对过去情况 的推测。例如：You must be hungry after a long walk.长途步行之后你一定饿了。They must be waiting for us. Let' s hurry up.他们一定在等我们。让我们快点走吧。You must have left your bag in the theatre.你准是把你的包丢在剧院了。You can'

3、; t be hungry, you have just had your dinner.你现在不可能觉得饿，你刚吃过饭。can' t be get ting betterHe wears glasses all the time, his eyesight他一直带着眼镜，他的视力不可能在好转。He has no idea what the book is about, he can' t have read it very careful ly.他一点也不知道这本书是关于什么的 , 他一定没有仔细读过此书。二、表示把握不大的推测即可能性时，用can和may,常译为“也许，可能

4、”。may用于肯定句与否定句，一般不用于疑问句。 can 常用于疑问句，一般不用于肯定 句。例如：The news may or may not be true ?这消息也许是真的，也许不是真的。At the moment she may be playing with her classmates?此刻她可能正在和同学们玩。Anna might not have seen Tom yesterday.安哪昨天可能没有看见汤姆。魏芳会在哪里呢？What can they be quarrelling about?他们可能在争吵些什么呢？Can she have lost the book?她可

5、能已把那本书丢了？ 跟踪小练习：从 A、 B、 C、 D 四个选项中 , 选出可以填入空白处的最佳选项1. Jenny with him at that time, for I was having dinner withher in my home ?A. can" t have beenB. mustn* t have beenC. must have beenD. may have been2. It is cold in the room. They have turned off the heating.A. mustB. ought toC. shouldD. could

6、3. Someone is knocking at the doorWho it be at this hour of day?A. may B? canC. mustD. should4. I didn* t hear the phone ? I asleep ?A. must beB. must have beenC. should beD. should have been5. Johnson be a policeman. He is much too shortA. mayB. mustn' tC? shouldD. can" t6. Jack fell off a ladder yesterday, but he was all right.He is lucky. He himself badly.A. can have hurtB. could have woundedC? might have hurtD. must have wounded7. Who told you the news?Mary.I don* t remember clearly. It It Mary. She doesn' t know it.A. may have been; can' t b