如题所述
基本释义：当它们表示能力的时候，是一样的。如：
He can speak two foreign languages.
He is able to speak two foreign languages.
区别：
1. can只有两种时态, 即can 和could, 而be able to 有多种时态, 如was/were able to, will/shall be able to, have/has been able to等:
I’ll be able to drive the car in a week.
Through his diligent work, the deaf-mute has been able to read and write in a sign language.
2．表示过去通过努力终于做成了某事要用be able to，而不能用can。如：
I was able to swim to the bank after the boat turned over.
can 和be able to 都可以表示能力.can泛指一般的能力,而且只有两种形式,即:can, could．be able to 则主要指具体做到了某件事的能力，其形式主要是靠be 发生变化，所以形式比can 多．可以说：I can swim. I am able to swim. 但是不能说：All the people could escape from the big fire in time. 只能说：All the people were able to escape from the fire in time.
3．can能表猜测，be able to不能。can的这种用法主要用于疑问句和否定句。
Somebody is knocking at the door. Who can it be?
It can’t be our teacher who is knocking at the door.
4．can 可以表 “允许”, 与may可以互换, 此时不能用be able to 代替。如： Can /
5. can 是情态动词，只能用作谓语成分，be able to是普通动词短语，既可以作谓语，也可以作非谓语。如：
How I long to be able to communicate with the foreigners in fluent English!
6. be able to 后边接动词不定式表示一种实际情况时，其否定形式不是be not able to，而是cannot。如：
Were you able to catch the first bus yesterday morning?
7. 一般说来, be able to 后边的动词不定式没有被动语态。如:
I’m sure he is able to correct his mistakes in grammar.
He can speak two foreign languages.
He is able to speak two foreign languages.
区别：
1. can只有两种时态, 即can 和could, 而be able to 有多种时态, 如was/were able to, will/shall be able to, have/has been able to等:
I’ll be able to drive the car in a week.
Through his diligent work, the deaf-mute has been able to read and write in a sign language.
2．表示过去通过努力终于做成了某事要用be able to，而不能用can。如：
I was able to swim to the bank after the boat turned over.
can 和be able to 都可以表示能力.can泛指一般的能力,而且只有两种形式,即:can, could．be able to 则主要指具体做到了某件事的能力，其形式主要是靠be 发生变化，所以形式比can 多．可以说：I can swim. I am able to swim. 但是不能说：All the people could escape from the big fire in time. 只能说：All the people were able to escape from the fire in time.
3．can能表猜测，be able to不能。can的这种用法主要用于疑问句和否定句。
Somebody is knocking at the door. Who can it be?
It can’t be our teacher who is knocking at the door.
4．can 可以表 “允许”, 与may可以互换, 此时不能用be able to 代替。如： Can /
5. can 是情态动词，只能用作谓语成分，be able to是普通动词短语，既可以作谓语，也可以作非谓语。如：
How I long to be able to communicate with the foreigners in fluent English!
6. be able to 后边接动词不定式表示一种实际情况时，其否定形式不是be not able to，而是cannot。如：
Were you able to catch the first bus yesterday morning?
7. 一般说来, be able to 后边的动词不定式没有被动语态。如:
I’m sure he is able to correct his mistakes in grammar.
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第1个回答 2015-04-26
be 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。本回答被提问者和网友采纳
(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。本回答被提问者和网友采纳
