现实是：有时候你会失败。没有人优秀到不会失败，没有人强大到不会失败，也没有人聪明到不会失败。失败总会发生。
The reality is: sometimes you lose. And you're never too good to lose. You're never too big to lose. You're never too smart to lose. It happens.
Freedom is the right to live as we wish.
The Internet is a living, evolving entity that requires constant attention and care.
在计算学习的背景下，“可能近似正确”（PAC）学习的概念为理解学习算法的效率和可行性提供了一个框架。