The Liskov Substitution Principle is a fundamental concept in object-oriented programming, ensuring that derived classes can be used in place of their base classes without altering the correctness of the program.

文学的目的不是给出答案，而是提出问题。

个人的总是政治的。

So long as you have food in your mouth, you have solved all questions for the time being.

投资研发就是投资乳制品的未来。

当一扇幸福的门关起的时候，另一扇幸福的门会因此开启，但我们却经常看这扇关闭的大门太久，而忘了注意到那扇已经为我们而开启的幸福之门。