當值, 上班Sorry, I can't come with. I am on duty tonight, worst luck. 抱歉, 我不能和你一起去, 真倒楣今晚我值班。There is always one teacher on duty during study hour. 學習時間通常都有一位老師負責管理。
不當班, 下班Sailors like to go sight-seeing when they are off duty in a foreign port. 船員們在外國港口不當班時喜歡觀光。It seems that all the taxis in Chicago are off duty on Labor Day. 芝加哥所有的計程車似乎在勞工節那天都不開車。