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.
有一只唱歌的小鸟被关在笼子里，笼子被挂在窗户外面，当其他鸟都睡着的时候，她总是唱歌。有一天晚上，一只蝙蝠来了，抓住笼子上的条栅，问那只鸟为什么白天沉默晚上唱歌。“我这么做的理由很充分，”小鸟回答说，“我原来在白天唱歌，结果一个捕鸟人被我的声音吸引，张网抓住了我。从那以后，我便只在晚上唱歌了。”但是蝙蝠回答说：“你现在已经是笼中鸟，再这么做根本没有什么意义，如果你能在被抓前这样做，你现在还会是自由自在的。”
训诫：事后再警惕并没有用。