Mathematics is an art, and as an artist, you have to be honest with yourself.

儿童书籍应该挑战、安慰和激励。

质量从来不是偶然的；它始终是智慧努力的结果。

"The truth is not always beautiful, but the pursuit of it is."

The only thing you have to fear is fear itself.

发展挑战没有放之四海而皆准的解决方案。