里氏替换原则是面向对象编程中的一个基本概念，确保派生类可以替代其基类使用，而不会改变程序的正确性。

Education begins the gentleman, but reading, good company and reflection must finish him.

It is better by noble boldness to run the risk of being subject to half of the evils we anticipate than to remain in cowardly listlessness for fear of what might happen.

追求知识是最崇高的努力，因为通过理解，我们才能解开宇宙的奥秘。

这不是钱的问题。而是关于你拥有的人，你如何被领导，以及你理解多少。