我为孩子们写作，因为我曾经是一个需要书籍的孩子。
一个观念的效用决定了它在精神生活中的地位。
Profit is important, but purpose is what sustains a business long-term.
Duty is the most sublime word in our language. Do your duty in all things. You cannot do more. You should never wish to do less.
The key to successful investing is to minimize costs and taxes.
The definition of a good mathematical problem is the mathematics it generates rather than the problem itself.
每一个词都是选择，而每一个选择都是牺牲。