Knowledge and ability with 能, 会 and 可以

Mandarin has three ways to express the concept “can” or “may.” Like English, the distinction is hazy at times, and nobody sticks closely to any arbitrary rules.

Use 能 to express the ability to do something.

我能跑步.
I can walk.

我明天能去重庆
I can go to Chongqing tomorrow.

Use 会 to express the ability to use a learned skill.

我会说中文.
I can speak Chinese (Traditional).

我们都会弹吉他
We can all play the guitar.

Use 可以 to express being allowed to do something.

你可以叫我汤姆
You can call me Tom.

我可不可以用你的手机?
Can I use your mobile phone?

In this last example, we used the verb-not-verb structure for asking questions. As 可以 is two syllables, we just repeat the first: 可不可以.