The purpose of mental activity is successful living.
你可以成为任何你想成为的人。做你自己就好。
"You can't go back and change the beginning, but you can start where you are and change the ending."
你无法回到过去改变开头,但你可以从现在开始改变结局。
The structure of the international system, not the intentions of individual states, is the primary determinant of state behavior.