What are modal verbs?

Modal verbs express the meanings of ability, permission, possibility, and future.

Learning when to use 会 (huì), 能 (néng), 可以 (kě yǐ)
There are different ways to express "can" in Chinese, depending on what type of ability you’re talking about. There are 3 ways to say “can” in Chinese, which are 会 (huì),能 (néng), 可以(kě yǐ)。

Tips
To negate these words, simply add 不 (bù) in front of them.

Rule
  会
(huì)
能
(néng)
可以
(kě yǐ)
Permission/request ✔ ✔  
Ability in the sense of “know how to”   ✔ ✔
Possibility   ✔ ✔
Permission not granted     ✔
Impossibility   ✔  


Expressing “knowing how to/ abilities”会 (huì) or 能 (néng)
Both 会 (huì)or 能 (néng) can be used to express abilities.

Structure
[Subject] + 会 (huì)or 能 (néng) + [Verb] + [Object]

EXAMPLE
我会说 汉语
wǒ huì shuō hàn yǔ
I can speak Chinese. = I know how to speak Chinese.
我能开车
wǒ néng kāi chē
I can drive. = I know how to drive.


Expressing Permission 能 (néng)/ 可以 (kě yǐ)
能/ 可以 is used to ask for permission/ requesting. When you ask for something, you can ask in the way of 能/ 可以 or 能不能/ 可不可以.

We seldom answer or agree using 能, use 能 to ask/request only.

Structure
[Subject] + 能 or 可以 + [Verb] + [Object]

EXAMPLE
他能 帮助 你
tā néng bāng zhù nǐ
He can help you. = He is able to help you.
我 今天 不能去
wǒ jīn tiān bù néng qù
I can’t go today. = I am not able to go today.


Expressing possibility 能 (néng) or 可以 (kě yǐ)
能 or 可以 is also used to communicate possibility and is often used to ask for permission politely. In its negative form, 不能 (bù néng) or 不可以 (bù kě yǐ) means it's not possible.

Structure
[Subject] + 能 or 可以 + [Verb] + [Object]

EXAMPLE
他能/ 可以 帮助 你。
tā néng/ kě yǐ bāng zhù nǐ
He can help you. = He is able to help you.
我 今天 不能/ 不可以去。
wǒ jīn tiān bù néng/ bù kě yǐ qù
I can’t go today. = I am not able to go today.


Talking about the future 会 (huì)
Only 会 can be used to mean something is going to/ true/definite happen. It expresses that something in the future sure will happen. Sometimes it is also used to express trends or possibilities.

Structure
[Subject] + 会 + [Verb] + [Object]

SENTENCE POSSIBILITY
我 不会 和你 结婚。
wǒ bù huì hé nǐ jié hūn.
I won’t marry you.
True/ definite
你会 生我的气 吗?
nǐ huì shēng wǒ de qì ma?
Will you be mad at me?
Possible
我这样 打扮 会 好看吗?
wǒ zhè yàng dǎ bàn huì hǎo kàn ma?
Will I look good if I dress up like this?
Possible