这句话借用俗语，表达了命运无常、机遇变化的道理。

To light a candle is to cast a shadow.

Great deeds are usually wrought at great risks.

The world is a very complicated place, and it's not always easy to understand what's happening around us.

最好的肥料是农民的影子，没有什么能取代在田间的存在和关注。