It is because nations tend to stupidity and baseness that democracy is possible.

计算学习理论中的挑战在于理解学习算法的能力和局限性。

Sometimes, the hardest thing in life is to know which bridge to cross and which to burn.

起初他们忽视你，然后嘲笑你，接着与你对抗，最后你获胜。