To understand the present, we must understand the past.

"Courage is not the absence of fear, but the triumph over it."

预测未来的最佳方式就是创造未来。

The beauty of computer science is that it allows us to create worlds within worlds, limited only by our imagination.

强化是获得新行为模式的核心因素。

The real challenge is not to build a cheap house, but to build a house that is cheap to live in.

When you have to kill a man it costs nothing to be polite.

在你能爱别人之前，你必须先爱自己。