里氏替换原则是面向对象编程中的一个基本概念，它指出子类的对象应该能够替换超类的对象而不影响程序的正确性。
The Liskov Substitution Principle is a fundamental concept in object-oriented programming, stating that objects of a superclass should be replaceable with objects of a subclass without affecting the correctness of the program.
We must remember that we are not the only species that matters on this planet.
即使在最黑暗的时刻，只要记得点亮灯光，就能找到幸福。
生活并不会问我们想要什么。它给我们提供一些选择。
