我相信儿童书籍应该是美丽的物品，值得珍藏和反复阅读。

只有向后看才能理解生活；但要生活好，则必须向前看。

The study of mathematics is like air or gravity—it is everywhere, and you can't see it, but you know it's there.

无边界即是无限的。

我们都有裂痕，那是光照进来的地方。