The cage-bird and the bat 笼子里的鸟与蝙蝠

A singing-bird was confined in a cage which hung outside a window, and had a way of singing at night when all other birds were asleep. One night a bat came and clung to the bars of the cage, and asked the bird why she was silent by day and sang only at night. "I have a very good reason for doing so," said the bird: "it was once when I was singing in the daytime that a fowler was attracted by my voice, and set his nets for me and caught me. Since then I have never sung except by night." But the bat replied, "It is no use your doing that now when you are a prisoner. If only you had done so before you were caught, you might still have been free."

Precautions are useless after the event.

一只画眉鸟被囚禁在窗外挂着的一个笼子里，当其他鸟儿都酣睡时，她却在夜里唱歌。有一个夜晚，蝙蝠飞过来，抓住鸟笼的栅栏，问她为什么白天默默无声，却在夜里放声歌唱。小鸟回答说：“我这样做是有道理的，曾经有一次，当我在白天唱歌时，一个捕鸟人被我的歌声吸引，就用鸟笼子捉住了我。从此我只在夜里歌唱。”可是，蝙蝠却说：“你现在这样做根本没用了，因为你已经成为阶下囚。若是在被捉住之前这样做就好了，那样或许你依然是自由之身！”

待事情发生之后再预防，为时已晚。