Mike, I know that office hour is up now, but could you work during the weekend? 迈克，我知道该下班了，不过你周末能不能加个班?

Well, unfortunately I have got something on this weekend. 真对不起，周末我已有安排了。

Unfortunately, I must work overtime. 很不幸，我要加班。

Could you work overtime tonight? 你今晚能加班吗?

Could you stay late? 你能晚点儿下班吗?