He who refuses to do arithmetic is doomed to talk nonsense.
The most important thing in mathematics is to ask the right questions.
失去某人,最糟糕的莫过于,他近在身旁,却犹如远在天边。
人生最难的是知道该跨过哪座桥,又该烧掉哪座桥。
未经省察的人生不值得过。