duty 
英 [ˈdjuːtɪ]  美 [ˈdjuːtɪ] 
n. 责任；义务；职责；职务；税

例句：
It is a doctor's duty to preserve life. 

救死扶伤是医生的责任。

He felt he had a duty to look after his father's business. 

他觉得自己有责任照看父亲的生意。

People have a moral duty to work for a just world. 

为公正的社会而奋斗是每个人的道德责任。

I encourage everyone to do your duty tomorrow and continue to vote. 

我鼓励每个人明天都履行责任，继续投票。

Make it your duty to provide for your children's future. 

为孩子的将来未雨绸缪是父母不可推卸的责任。

I would like to stay at home, but I think duty calls. 

我很愿意待在家里，但我想还有工作等着我做。