You're supposed to turn in your key when you go off shift.你换班时应交还钥匙。I'm on duty until 2 p.m. and then Peter is coming to relieve me.我要值班到下午两点，两点以后彼得就会来换班。The man I was relieving in the observation post was impatient when I arrived.在观察哨等我换班的那个士兵在我到达的时候显得不耐烦了。