害怕死亡是无知的表现。

To say something is to perform an action， and to perform an action is to do something with words.

解释：要量力而行，实力达得到就进攻，达不到就撤退。

测量可测量的，并使不可测量的成为可测量的。

家庭是文明的核心。

To travel is to write with your feet.