In short

A modal verb (an “auxiliary,” 能愿动词 néngyuàn dòngcí) goes right before the main verb and says something about it: whether you can, may or want to do it. The five A1 workhorses are 会 (huì, know how to / likely to), 能 (néng, be able to), 可以 (kěyǐ, be allowed to), 想 (xiǎng, want to), and 要 (yào, want / be going to). They all negate with 不 - never 没 - and the aspect markers 了 and 过 never attach to the modal itself.

The rule

The frame never changes:

Subject + (adverb) + Modal + Verb (+ Object)

So “I want to drink tea” is 我想喝茶 (wǒ xiǎng hē chá): subject 我, modal 想, verb 喝, object 茶. The modal sits between the subject and the verb, and any adverb (like 很 or 都) goes in front of the modal, not the main verb: 我很想去 (wǒ hěn xiǎng qù, I really want to go).

The three “can” words. English “can” hides three different Chinese ideas - pick by why something is possible:

• 会 (huì) - a learned ability, a skill you acquired: 我会游泳 (wǒ huì yóuyǒng, I can swim), 我会说中文 (wǒ huì shuō Zhōngwén, I can speak Chinese). 会 also predicts likelihood: 明天会下雨 (míngtiān huì xià yǔ, it’ll rain tomorrow).
• 能 (néng) - a capability given the circumstances: being free, strong or well enough. 你今天能来吗？ (nǐ jīntiān néng lái ma?, can you come today?) asks whether conditions allow it, not whether you know how. 能 also covers capacity: 他能吃五个 (tā néng chī wǔ ge, he can eat five).
• 可以 (kěyǐ) - permission, “may / be allowed to”: 这里可以抽烟吗？ (zhèlǐ kěyǐ chōuyān ma?, is smoking allowed here?), 你可以走了 (nǐ kěyǐ zǒu le, you may go now).

The line between 能 and 可以 is thin - both work for “am I allowed / able to,” and speakers often swap them. Reserve 会 for skill and prediction, and you avoid the biggest slip.

Wanting: 想 vs 要. 想 (xiǎng) is the soft one, “would like to,” a wish: 我想去北京 (wǒ xiǎng qù Běijīng, I’d like to go to Beijing). 要 (yào) is firmer - a decision or plan, “want to / be going to / will”: 我要去北京 (wǒ yào qù Běijīng, I’m going to Beijing). Unlike the others, 要 also takes a plain noun to mean “want (to have)”: 我要一杯咖啡 (wǒ yào yì bēi kāfēi, I want a coffee).

Negation - always 不, and mind 要. Modals are negated with 不, never 没: 不会 / 不能 / 不可以 / 不想. Two traps: 不可以 means “may not, it’s forbidden,” a real prohibition; and 要 normally does not negate to 不要 in the “want” sense - “don’t want to” is 不想, and the plain future negative is just 不 + verb (我明天不去, wǒ míngtiān bú qù). 不要 by itself is the command “don’t!” and belongs to Imperatives (请/别/不要).

Questions and short answers. Make a yes/no question with 吗, or use the A-not-A form by doubling the modal: 会不会 / 能不能 / 可不可以 / 想不想 / 要不要. A modal can answer on its own: “会。” (huì, “Yes, I can”), “不能。” (bù néng, “No, I can’t”).

Forms & patterns

Which word for which meaning:

Negative and question forms:

Examples

Common mistakes

• 我没会说中文。 -> 我不会说中文。 (Wǒ bú huì shuō Zhōngwén.) - Modals are negated with 不, never 没.
• 我想一杯咖啡。 -> 我要一杯咖啡。 (Wǒ yào yì bēi kāfēi.) - 想 + a noun means “miss / think of.” To want an object, use 要 (or 想要).
• 我说会中文。 -> 我会说中文。 (Wǒ huì shuō Zhōngwén.) - The modal comes before the main verb, not after it.
• 你会来吗？ (meaning “are you able to come?”) -> 你能来吗？ (Nǐ néng lái ma?) - 会 is skill or likelihood; whether circumstances let you come is 能 (or 可以).
• 我会说中文了过。 -> 我会说中文。 - Modals never carry 了 or 过 themselves; leave aspect off the modal.

Tips

• Sort the three “cans” by the reason: 会 = I learned it, 能 = conditions allow it, 可以 = someone permits it. When in doubt between 能 and 可以, either is usually safe.
• 想 is a wish, 要 is a decision. “我想去” leaves the door open; “我要去” means it’s settled - so 要 can sound blunt, and 想 is the polite everyday choice for “I’d like to.”
• Watch the tone sandhi on 不: it’s bú before a 4th tone (不会 bú huì, 不要 bú yào) but stays bù elsewhere (不能 bù néng). And 可以 is written kěyǐ but said kéyǐ, two 3rd tones colliding.
• False-friend alert: don’t reach for 不要 to mean “I don’t want to” - that’s the command “don’t!”. Say 不想.