1. 表示“责任”“义务”，视含义的具体或抽象可用作可数或不可数名词。如：
Everyone has a duty to his country. 为国效劳，人人有责。
He did it out of a sense of duty. 他做此事是出于一种责任感。
表示作为工作一部分的“职责”或“职务”等，通常用复数形式。如：
Don’t forget your duties as a soldier. 不要忘记你作为一名战士的职责。
Your duties include checking the post and distributing it. 你的职责是检查和发送邮件。
2. 表示有责任或义务做某事，其后可接 to do sth 或 of doing sth。如：
A man has a duty to earn money for his family. 男人有挣钱养家的责任。
Every citizen has the duty of defending his country.
As a soldier, it's my duty to serve my country and people！
作为一名军人，为祖国和人们服务是我的义务！
Everyone must do one's part while on duty to protect the safety of the school ground.
在执勤时，每个人都要尽职，确保校园的安全。
I usually go on duty at 8 a.m.
我通常上午八点上班。
It's my duty to help him.
帮助他是我的责任。
※The paramount duty of Congress is to stop deficiencies by the restoration of that protective legislation which has always been the firmst prop of the Treasury.——William Mckinley, American president 国会的最高职责是恢复始终是国家财政最坚实支柱的保护性立法，以制止财政赤字。美国总统 科金利.W.
※Only they who fulfill their duty in everday matters will fulfill them on great occasions. 只有在日常事务上尽责的人，才能在重大事情上尽责。
