“木已成舟”，汉语成语，意思是指树木已经做成小舟（the wood is already made into a boat），比喻事情已成为不可改变的定局。可以翻译为“what is done cannot be undone，what is done is done或water over the dam”。

例句：

好吧，木已成舟不是吗？我们能不能就别再提了。

Okay, what's done is done, right？Can't we just move on?