Do not cry over spilt milk!

不要做无益的后悔。

I don't cry over spilt milk, you know?

不要为溢出的牛奶哭泣（后悔无用），不是么？

There is a proverb say: don't cry over spilt milk.

谚语说：不要为打翻的牛奶哭泣。

Don't cry over spilt milk. Unless you can cry milk.

不要为倒掉的牛奶哭泣，除非你能哭出牛奶。

Don't cry over spilt milk for your lost pen, you'd better buy a new one.

不要为丢失的钢笔难过了，你最好另买一只新的。