call it a day/night这个表达的意思是“到此为止”，可以表示暂时停止，也可以用作俚语，表示某事已经完全结束了。

Right guys, you've worked really hard. I think it's time to call it a night, I'll see you all again tomorrow.

是的，伙计们，你们真的很努力。我觉得该结束了，我们明天再见。

Neither of us was happy in the relationship, so we decided to call it a day.

我们俩对这段感情关系都不满意，所以决定分手。