I say luck is when an opportunity comes along and you're prepared for it.

灵魂的净化比身体的净化更重要。

The power of abstraction is that it allows us to ignore details that are not relevant to the task at hand.

"There is no substitute for books in the life of a child."

人心充满私欲，所以危险；道心符合天理，所以精妙。