说出口的，就是结束且完成的。

The true cost of coal isn't just in its price, but in how we manage its consequences.

Those who cannot remember the past arecondemned to repeatit.

A teacher must have a healthy body, the skills of a farmer, the mind of a scientist, the interest in art, and the spirit of social reform.

追求真理需要相当大的努力，这就是为什么只有很少人愿意出于对知识的热爱而去追求真理，尽管上帝在人的心灵中植入了对这种知识的自然渴望。