All who joy would win must share it. Happiness was born a twin.
里氏替換原則是面向?qū)ο缶幊讨械囊粋€基本概念，它指出子類的對象應(yīng)該能夠替換超類的對象而不影響程序的正確性。
最大的風(fēng)險是不冒任何風(fēng)險。在一個快速變化的世界里，唯一注定失敗的策略就是不冒險。
The natural effort of every individual to better his own condition， when suffered to exert itself with freedom and security， is so powerful a principle that it is alone， and without any assistance， not only capable of carrying on the society to wealth and prosperity but of surmounting a hundred impertinent obstructions with which the folly of human laws too often encumbers its operations.