May,might, could表可能性用法

May, might, can, could 表可能性

1)may/might 表示‘可能’，往往可以交替使用，并无时间上的差异，只是用might 在口气上比用may 更加不甚肯定，从而比较婉转。

may/might 既可表示现在的‘可能’：

e.g. It may/might be true.

He may/might be still waiting at the door.

也可表将来的‘ 可能’ ：

e.g. He may/might leave tomorrow.

He may/might not to leave next week.

He may be in the office.

2)用can /could 表示现在的‘可能’，在口气上could 比较婉转。

e.g. That’s not mine. Whose can it be ?

It could be John's. 用can ，表示‘可能’，较多的用于否定句中，而could 则不受此限。

e.g. If you don’t have a guide, you could lose your way.

(=it’s possible for you to lose your way.)

It can’t/couldn’t be true.

The moon cannot always be at the full.

can 与may 的区别

(=It’s possible for the road to be blocked.)

The road may be blocked.

(=It’s possible that the road is blocked.)

Another example:

Mr. Reed is in poor health. He can be ill at any time.

Mr. Reed looks pale. He may be ill.

She may/might have missed the train.

She can’t/couldn’t have missed the train.

用‘might/could+ 不定式完成体’ 有时可以表示本来可能发生但没有发生的，或者本来可能完成却没有完成的动作。

e.g. You might have killed yoursel

f. （你本来可能送命的。）

You might have finished the work last week.

summary

句

型

情态动词释义例子

肯定句May[ fml ],

might,

表示某事可能发生或称为现

实

He may/might be still waiting at the door. could

人们常用以表示所说的话并

不肯定

If you have a guide, you could lose your way.

can 是某件事在某个特定情况下

发生的可能性

The temperature can sometimes reach 35 ℃ in

July.

疑问句Could( n’t ),

can

be likely,

might[ fml ]

Could it be that you don’t want to leave?

否定Can’t, couldn’t 表示某件事不可能是事实

There are plans to rebuild the town centre, but

it can’t/couldn’t happen for another ten years.

句

May not, might not 表示可能某件事不是事实

There are plans to rebuild the town centre, but

it may not/might not happen for another ten

years.

一、表示对过去情况的推测或估计

may ／might have done 肯定句可能／大概（已经）…… 否定句可能还没有……

can ／could have done 否定句不可能（已经）……疑问句可能／也许（已经）……了吗？说明：1 might ／could有时并不是may ／can的过去式，而是表示一种委婉的语气或更小的可能性。 2 might have done有时可用于疑问句中，此时might就相当于can ／could。

比较may和might

1、表示允许或请求；表示没有把握的推测；may 放在句首，表示祝愿。

例如：

May God bless you!

愿上帝保佑你！

He might be at home.

他可能在家。

注意：might 表示推测时，不表示时态，只是可能性比may 小。

2、成语：may/might as well，后面接不带to 的不定式，意为"不妨"。

例如：

If that is the case, we may as well try.

如果情况确实如此，我们不妨试一试。

典型例题

Peter _come with us tonight, but he isn't very sure yet.

A. must

B. may

C. can

D. will

答案B. 表可能性只能用may。此句意可从后半句推出。

Attention

推测的否定形式，疑问形式用can't, couldn't表示。

例如：

Mike can't have found his car, for he came to work by bus this morning.

迈克一定还没有找回他的车，因为早上他是坐公共汽车来上班的。

练习

1、---Could I borrow your dictionary?

---Yes, of course, you__________.

A. might

B. will

C. can

D. should

答案C. could表示委婉的语气，并不为时态。答语中of course，表示肯定的语气，允许某人做某事时，用can和may来表达，不能用could或might。will 与you连用，用来提出要求或下命令。should与you 连用，用来提出劝告。

2．I thought you _______ like something to read，so I have brought you some books．（MET 1986）

A．may B．might C．could D．must

由题意可知被猜测的时间是（过去）将来，没有客观事实根据，猜测语气要求最弱，所以正确选项是B。

3．Peter ______ come with us tonight，but he isn't sure yet．（MET 1993）

A．must B．may C．can D．will

由题意可知被猜测的时间是将来，没有客观事实根据，猜测语气要求最弱，所以正确选项是B。

4．Mary _______be in Paris，for I saw her in the town only a few minutes ago．（MET 1994）A．mustn't B．can't C．shouldn't D．may not

由题意可知被猜测的时间是现在，有客观事实根据I saw her in the town a few minutes ago，猜测语气要求最强，所以正确选项是B（can't是must的否定式）。

5.—There were already five people in the car but they managed to take me as well．

—It _______ a comfortable journey．（NMET 1995）

A．can't be B．shouldn't be C．mustn't have been D．couldn't have been

由题意可知被猜测的时间是过去，有客观事实根据there were already five people．．．take me as well，猜测语气要求最强，所以正确选项是D。

6．-Are you coming to Jeff's Party？

—I'm not sure．I ________go to the concert instead．（NMET 2000）

A．must B．would C．might D．should

由题意可知被猜测的时间是将来，没有客观事实根据，猜测语气要求最弱，所以正确选项是C.