相对论是一种原理性理论，而非构造性理论。

"You can't go back and change the beginning, but you can start where you are and change the ending."

【大意】一个国家如果没有正义，即使再强大也定会灭亡。一个人如果没有良善的志趣，即使勇猛也必会遭遇挫伤。

A human being needs to suffercWhen one suffers， one becomes strong.

摆脱爱情痛苦的唯一方法是爱得更多。