知乎，让每一次点击都充满意义 —— 欢迎来到知乎，发现问题背后的世界。知乎，让每一次点击都充满意义 —— 欢迎来到知乎，发现问题背后的世界。b : very long-proven apply regarded as unwritten regulation c : recurring follow Custom tends to make all points straightforward.) is 'the general r