Every mental state exists for a purpose; to understand it, we must ask what function it serves in the broader system of behavior.

The training and improvement of labor are effective ways to increase productivity.

"I'm not a diva. I'm just very passionate about what I do."

"The best leaders are those who can listen as well as they can speak."

国际政治是一项残酷而危险的事务，而且很可能继续保持这种状态。