对民主的最大威胁不是来自外部敌人，而是来自内部腐败和公民美德的丧失。
The greatest threat to democracy is not from external enemies but from internal decay and the loss of civic virtue.
译文：大道没有具体的形态，那么内心要凭借什么去领悟呢?关键在于每个人自身的智慧和见识是否高明。
The hardest decisions often yield the greatest rewards.
Technological innovation is the fundamental way to solve the problems of the coal industry.