There's the kind of grammar that lives inside your brain, and if you're a native speaker of a language or a good speaker of a language, it's the unconscious rules that you follow when you speak that language.
一种是在你脑子固定形成的语法 如果你以某一语言为母语 或者你能流利地说某种语言 是你在说那种语言时 所遵循的潜规则