The more we learn about the universe, the more we realize how much we have yet to discover.

Every age has its massive moral blind spots. We might not see them, but our children will.

Thinking is behavior. The muscular habits learned in overt speech are responsible for implicit or internal speech (thought).

化合价的概念是理解化学键的关键。

尽管困难，但约束自己去做你知道是正确和重要的事情，是通往自豪、自尊和个人满足的大道。

数学的本质在于它的自由。