情态动词分类及运用（情态动词------表示）

1：表示“能力”

表示能力，可用 can , could ,be able to .can 既能表示现在的“能力”，也能表示将来的“能力”。

eg:

Look ! i can do it .

I can't do it now ,but i can do it later.

用can 表示现在的“能力”，即可表示做某桩具体事情的“能力”

eg:

I can climb this cliff.

Is there anything i can do for you ?

也可泛指一般的“能力”

eg:

He can drive a car .

He is only four ,but he can read.

She can't play the piano.

Fire can not destroy gold.

can表示“能力”与be able to 同义，在许多情况下可以交替使用。

eg:

As i have got enough money, i can /am able to help her .

尤其是将来的“能力”，通常用will/shall be able to 表示。

eg:

表示过去的“能力”，可用could和was /were able to ,但在肯定句中，could 所表示的“能力”仅是泛指过去的一般能力。

eg:

She could play the piano when she was only six.

At that time i could still read without spectacles.

如果要表示过去做某桩具体事情的“能力”，通常不用could,而用 was /were able to （以及managed to ）.

eg:

He was able to swim halfway before he collapsed.

He was able to translate the article without a dictionary .

I talked a long time ,and in the end i managed to make her believe me .

上述could 与was /were able to 用法上的区别仅是就肯定句而言，在否定句中却无此限制，could 即可表示过去的一般能力，也可表示过去做某桩具体事情的能力。

eg:

I couldn't /wasn't able to play the piano when i was at school.

He got so drunk that he couldn't /wasn't able to find the front door .

表示“能力”，除用can ,could ,be able to 外，还有其他表示法。

eg:

He has the ability to deal with complicated problems.

You are capable of better work than this .

He is capable of running a mile in four minutes.

2:表示“可能”

表示“可能”，可用may ,might ,can ,could 。 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 即可表示现在的“可能”

It may /might be true .

He may/might be still waiting at the door .

He may not /might not live near the theatre.

也可表示将来的“可能”

He may /might leave tomorrow .

He may not /might not leave next week .

在疑问卷中表示“可能”，须用can 而不用may .

eg：

Where can he be ?

He may be in the office .

Can they have missed the bus ?

Yes,they may have .

在肯定陈述句中，用can 表示“可能”与用may表示“可能”，往往产生含义上的微妙差别，用can 表示“可能”往往指逻辑上的“可能性”，而用may 表示“可能”则指事实上的“可能性”。

The road can be blocked .=(It is possible for the road to be blocked )

The road may be blocked .=（It is possible that the road is blocked ）

又例如

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

Mr Reed looks pale .He may be ill.

表示过去的“可能”，可用may/might 不定式完成时或不定式完成进行时，在这里用may/might ，也只有口气上婉转程度的差异，而没有时间上的区别。

eg:

He may/might have been hurt .

She may/might have missed the train .

用might/could 不定式完成时，有时可以表示本来可能发生，或者本来可能完成却没有完成的动作。

eg:

You might have killed yourself .(你差点儿送了命）

You might have finished the work last week.

I could have reported you .(我本可以告发你）

I could have passed the examination ,but i failed .

表示“可能”，除用may /may not ,can /can't 外，还有一些形容词、副词、以及相应的名词也都能表示“可能”

Frost is possible ,although unlikely at this time of year .(下霜是可能的，尽管在这个时节下霜可能性不大）

She was possibly the greatest writer of her generation .(她可能是她那一代人中最伟大的作家）

There is possibility of his coming /that he'll come .

It is perhaps the best known of her works .

如果要表示很大的可能性，可用 probable ,probably ,likely ,probability,likelihood 等。

eg:

It is probable /likely that he will come .

He is likely to come .

He's probably stuck in a traffic jam.(他很有可能遇上了堵车）

There is little probability of his succeeding /that he will succeed .(他不大可能会成功）

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