助动词：可以

**Meaning 1 — Permission (asking and giving)** 可以 is used to ask whether something is allowed or to grant permission. - Asking: 可以进来吗？(May I come in?) - Granting: 你可以走了。(You may leave now.)

**Meaning 2 — Possibility / feasibility** 可以 also expresses that something is logically or circumstantially possible. - 这里可以停车。(You can park here. / Parking is allowed here.)

**Negation: 不可以** 不可以 means "not allowed" or "must not" — it carries a sense of prohibition. Informally, 不行 (bù xíng) is used with the same meaning. - 这里不可以抽烟。(Smoking is not allowed here.) - 不行，你不能这样做。(No, you can't do that.)

**Polite question formula: 可以 + V + 吗？** This is one of the most common and natural ways to politely request permission in Chinese. - 我可以坐这里吗？(May I sit here?) - 可以帮我一下吗？(Could you help me for a moment?)

**Comparing 可以 vs 能 (néng)** - 能 focuses on physical ability or circumstantial capacity: 我能吃五碗饭。(I can eat five bowls of rice — physical capacity.) / 他感冒了，不能来。(He has a cold and can't come — circumstance prevents it.) - 可以 focuses on permission or logical feasibility: 这里可以停车。(Parking is permitted here.) / 你可以用我的手机。(You may use my phone.) - Both can sometimes overlap, but 可以 sounds more polite when asking for permission.

**Comparing 可以 vs 会 (huì)** - 会 describes a learned skill or acquired ability: 我会说中文。(I know how to speak Chinese — I've learned it.) - 可以 describes permission or possibility: 我可以说中文。(I'm allowed to / I can speak Chinese here.) - When "know how to" is the meaning, use 会, not 可以.

**When NOT to use 可以** Do not use 可以 to express a learned skill. 我会开车 (I know how to drive) is correct; 我可以开车 shifts the meaning to "I'm allowed to drive."

**Special use: 可以 as an adjective meaning "not bad / decent"** 可以 can stand alone or follow 还 to mean something is acceptable or passable. - 这个菜还可以。(This dish is not bad / decent.) - 你的中文还可以！(Your Chinese is pretty decent!)