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be able to 用法

be able to 用法

e able to与can用法区别:

(1) be able to 强调通过努力而获得的能力,而can则强调自身已具有的能力.如:

She can sing the song in English. 她能用英语唱这首歌.

He will be able to sing this song in English in a few minutes, too. 几小时之后,他也能用英语唱这首歌.

(2) be able to 强调一种结果,而can只强调一种可能.如:

Luckily, he was able to escape from the big fire in the end. 幸运的是,他终于逃出了大火.

If he got here a few hours earlier, I could save him. 要是他早几小时来,我还能救他.

(3) be able to 可以有各种时态;而can只有一般现在和一般过去两种时态.如:

I could help you last night, but you didn’t come. 昨天晚上我能帮你,而你又没来.

Can you see it there? 你能看见它在那儿吗?

He is / was / will be able to help you. 他能帮你的忙.

(4) can可用于表示可能性,推测,允许等情况,而be able to通常不这样用.

can的用法和意义:

(1) 表示能力,意思为“能,会”.如:

I can sing this song in English. 我能用英语唱这首歌.

Can you tell me where the museum is? 你能告诉我博物馆在哪吗?

(2) 表示许可,意思是“可以”.如:

You can use my pen instead 你可以用我的笔.

Can I come in? 我可以进来吗?

(3) 表示推测,意为“可能,会”,主要用于否定句和疑问句中.如:

Can he be there too? 他也会在那儿吗?

He can’t have finished his work. 它不可能把工作做完了.

【说明】有时也用于肯定句中表示“有时”,或表示理论上的可能性.如:

She can be very unpleasant. 她有时很令人讨厌.

Even experienced teachers can make mistakes. 即使是有经验的教师也可能出错.

(4) 表示惊讶,通常用于疑问句、否定句和惊叹句中.如:

Can this be your reason? 这难道就是你的理由?

How can you say it like that? 你怎么能那样说话呢?

注意:从理论上说,could是can的过去式,但在某些场合中,could可用来代替can,表示现在的情况,只是语气较can委婉,此时,若用could来提问题,回答时,应该用can,而不用 could.如:

Could you answer me a question? 请回答我一个问题好吗?

Yes, I can. / No, I can’t. 好./ 不行.

希望对你有帮助 如有疑问 请在线交谈 祝你考上理想的学校 O(∩_∩)O