AEIS核心词汇辨析：can和be able to用法上的区别

　　在平常的英语学习中，同学们可能缺少系统的词语辨析训练，所以AEIS考试遇到这类考点总是失分。今天小编继续分享AEIS核心词汇讲解，希望帮助大家扫清词语辨析的障碍！

　　can和be able to

　　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.

　　以上就是小编为大家整理的关于AEIS英语词汇辨析，希望对大家学习有所帮助。更多上海AEIS培训学校、AEIS报名资料等问题可以咨询我们。