'Accidents will happen', as the saying goes.

常言道：“意外事，总难免。”

As the saying goes — it's no use crying over spilt milk.

常言道：覆水难收，后悔也于事无补。

When would they be hired again? Perhaps, as the saying goes, when pigs fly.

他们什么时候会被重新雇用？也许正像俗话说的，等到猴年马月吧。

As the saying goes, barking dogs don't bite.

常言说的好，会叫的狗不咬人。

As the saying goes: Work while you work, play while you play.

俗话说得好，该工作时工作，该娱乐时娱乐。