The only valid data for psychology are observable behaviors.

The Vietnamese people deeply love independence, freedom, and peace. But in the face of a threat to their country's independence, the Vietnamese people would rather sacrifice everything than lose their country and be enslaved.

数学不仅仅是一系列抽象概念的集合，而是一种让我们理解宇宙的语言。

领导力是激励他人实现他们曾经认为不可能的事情。