理解学习问题的计算复杂性对于开发高效算法至关重要。

There is no love that’s so right as admiration-based love, and that love should include the instructive dead. Somehow, I got that idea and I lived with it all my life and it’s been very very useful to me.

Hope is not an emotion, but a choice.

A good illustration doesn’t just decorate the text—it expands it.

思想掠过我的心上，如一群野鸭飞过天空。我听见它们鼓翼之声了。

The first fruit of this imagination - and the first lesson of the social science that embodies it - is the idea that the individual can understand his own experience and gauge his own fate only by locating himself within his period, that he can know his own chances in life only by becoming aware of those of all individuals in his circumstances.