1. 职务;义务
    Duty is work that you have to do for your job.

    e.g. Staff must report for duty at their normal place of work...
           职员必须在平时上班的地方签到。
    e.g. My duty is to look after the animals.
           我的责任就是照看这些动物。

2. 职责;任务;本职工作
    Your duties are tasks which you have to do because they are part of your job.

duty

    e.g. I carried out my duties conscientiously...
           我一丝不苟地履行我的职责。
    e.g. He was relieved of his duties as presidential adviser.
           他被撤销了总统顾问一职。

3. 责任;本分
    If you say that something is your duty, you believe that you ought to do it because it is your responsibility.

    e.g. I consider it my duty to write to you and thank you.
           我认为写信向你表达谢意是我的责任。

4. 税
    Duties are taxes which you pay to the government on goods that you buy.

    e.g. Import duties still average 30%.
           进口税的平均水平仍然在 30%。
    e.g. ...customs duties...
           关税

5. 下班/上班;不值班/值班
    If someone such as a policeman or a nurse is off duty, they are not working. If someone is on duty, they are working.

    e.g. I'm off duty...
           我下班了。
    e.g. Four officers were told to go off duty and rest at home...
           四名官员已经被通知停职在家休整。