当一个人情绪低落的时候，他会格外地喜欢看日落。

I don't think that you have any insight whatsoever into your capacity for good until you have some well-developed insight into your capacity for evil.

对于系统，翻版的模拟是在控制图中添加一个创建循环的边，而不仅仅是一个附加节点。