The aim of psychology is to describe the structure of experience.

语言是一个自由创造的过程；其法则和原则是固定的，但生成原则的运用方式是自由且无限多样的。

Some people are extraordinarily good at knowing the limits of their knowledge because they have to be.

可持续性不是一种选择；它是农业未来的必需品。