{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。gap - a difference (In particular an unfortunate difference) among two viewpoints or two views or two circumstancesWould like to thank TFD for its existence? Notify a buddy about us, include a hyperlink to this page, or visit the webmaster's web si