会 for learned skills and likely events
会 huì describes a skill someone has learned, especially languages and activities. It can also express that something is likely to happen.
Wǒ huì shuō yìdiǎn Zhōngwén. — I can speak a little Chinese.
Tā huì kāichē. — She can drive.
Míngtiān huì xiàyǔ. — It will probably rain tomorrow.
能 for circumstances and physical ability
能 néng focuses on whether circumstances or physical ability make an action possible. It is useful for asking whether someone has time, energy, or permission from a practical situation.
- 你能帮我吗? Can you help me?
- 今天我不能去。 I cannot go today.
- 你能听见吗? Can you hear?
可以 for permission or an acceptable option
可以 kěyǐ asks whether something is allowed or acceptable. It is common in requests and practical questions.
May I sit here?
Can I use cash?
Could you say it again?
A useful reply is 可以 for permission and 不可以 for “that is not allowed”.
要 for intention or a request
要 yào can mean want, need, or intend to do something. In a restaurant, 我要 is a normal way to state what you would like. With a time phrase, it often means “going to”.
- 我要一杯茶。 I would like a cup of tea.
- 我明天要上班。 I have to work tomorrow.
- 你要不要一起去? Do you want to go together?