历史是一个庞大的预警系统。
The utility of an idea determines its place in mental life.
现今的士人用身于世,还不如商人使用一枚钱币时谨慎。 
【释义】若不是在正午半夜的时候,连太阳和月亮都看不见。描绘了三峡峡谷幽深、遮天蔽日的景象。
When something is important enough, you do it even if the odds are not in your favor.