会, 能, 可以: can
能愿动词 / modal verbs
Tone colorsā tone 1á tone 2ǎ tone 3à tone 4a neutral
Subject + 会 / 能 / 可以 + Verb
Three verbs for "can", with nuances:
会 = know how to, thanks to learning: 我会游泳 (I can swim). Also future likelihood (明天会下雨).
能 = physical ability or circumstances allowing it: 我今天不能游泳，我感冒了 (I can't swim today, I have a cold).
可以 = permission: 这儿可以游泳吗？(Is swimming allowed here?)
To deny permission, 不能 is usual (不可以 sounds stern): 这儿不能抽烟.
Examples
你会打乒乓球吗？
Nǐ huì dǎ pīngpāngqiú ma?Can you play table tennis?
我脚疼，今天不能跑步。
Wǒ jiǎo téng, jīntiān bù néng pǎobù.My foot hurts, I can't run today.
这里可以踢足球吗？
Zhèlǐ kěyǐ tī zúqiú ma?Can we play football here?
他一分钟能跑四百米。
Tā yì fēnzhōng néng pǎo sìbǎi mǐ.He can run 400 metres in a minute.
Common mistakes
✗ 我可以说中文 (for "I speak Chinese") → ✓ 我会说中文.
✗ 我会游一千米 (measured performance) → ✓ 我能游一千米.