be able to和can都可表示能够做某事，但有所区别。be able to 和can的区别讲解如下。

1.时态区别
can用于一般现在时，一般过去时用could，不能再用于其他时态。
be able to可用于各种时态。

[造句]
He can dance. 
他会跳舞。
He could dance when he was a boy.
当他是个男孩子的时候，他能够跳舞。

He is able to dance.
He was able to dance when he was a boy.
He will be able to dance.
He has been able to dance.

2.用be able to不用could的情况
若表示过去已完成某次具体的动作，要用be able to，不用could
Although he was hurt, he was able to run fast. 
虽然他受伤了，但是他还能跑的快。（他已经跑完了）
Although she was weak, she was able to speak.
虽然她很脆弱，但是她能说话。（已经说完了）
Luckily, the plane was able to land safely.
幸运的是，飞机能够安全着陆。（飞机已安全着陆）

3.can除了表示能力，还可表示推测等，而be able to不行
Andy is on holiday. He can't be at work. 
安迪在度假，他不可能在上班。

以上就是be able to 和can的区别。