A proof is a device for convincing someone else that a mathematical statement is true.
Can a man still be brave if he’s afraid. That is the only time a man can be brave.
你无法改变过去，但你可以塑造未来。
【译文】 司马牛忧伤地说：“别人都有兄弟，唯独我没有。”子夏说：“我听说过：‘死生有命，富贵在天’。君子敬业而不犯错误，对人恭敬而有礼。四海之内，皆兄弟。君子担心什么没有兄弟？”
译文：一心想完成替君主收复国家失地的大业，争取生前死后都留下为国立功的美名。可叹如今满头白发已经丛生!
The true measure of a civilization is how it treats its weakest members.