江河的水之所以浩浩荡荡，并非只由一个源头流出来；无比珍贵的皮衣，并非只由一只狐狸腋下的毛皮所能制成。

The only real prison is the one we build for ourselves.

We must balance economic growth with ecological preservation—there's no other option.

The poor are often more entrepreneurial than the rich, but they lack the tools to succeed.

当儿童还没有发展起控制能力的时候，“让儿童想干什么就干什么”是与自由观念相违背的。

To do mathematics is to explore a universe of ideas, where the only limit is your imagination.