Sometimes, a child cries when they reach for something at the table and knock over the cup that had their milk in it. Once something like that happens, little can be done except to clean up the spill. It does no good to cry about it. This is a lesson people need to learn over and over again as they go through life: be careful.
悔恨無濟於事。
別為打翻的牛奶哭泣，意思就是：不要做無益的追悔。這誠然是我們一生當中，亟需儘早學會的功課。與君共勉，好自為之！