天不为人之恶寒而辍其冬，地不为人之恶险而辍其广，君子不为小人之匈匈而易其行。
上天不会因人们害怕寒冷而让冬天消失，大地不会因人们厌恶险峻而停止其广大。君子不会因小人喧嚣而改变自己的品行。
The training and improvement of labor are effective ways to increase productivity.
I believe in such cartography – to be marked by nature, not just to label ourselves on a map like the names of rich men and women on buildings.
形式化方法的美在于它们能够提供关于系统行为的绝对保证。