沉痛的教训 meaning in English

bitter experience

I have learned a sad lesson today; and that is never to do anything in anger .
今天我得到了一个沉痛的教训，那就是，永远不要在发怒的时候处理任何事情。
After having suffering some contaminated events , people have realized that there is only one earth for us to dwell in , and we should protect the environment
经过了一些污染事件，吸取了沉痛的教训之后，现在人们已经意识到人类所赖以生存的地球环境只有一个，人类的文明并不仅仅是物质的极大丰富，生存环境的改善也是其中重要的内容。