duty, obligation, responsibility

　　duty n.指道義上的責任，強調自覺性，作可數名詞時指本職工作的任務。

　　His duty is to see that the business runs well.他的職責是保證生意良好運轉。

　　obligation n.指合同或法律上規定的責任，義務，強調其約束力。

　　Parents have a legal obligation to ensure that their children are provided with efficient education suitable to their age.父母有法律上的義務確保其子女受到適合其年齡的有效教育。

　　responsibility n.職責，強調對后果要負責任的意思。

　　His father is ill, and he has the responsibility of caring for him.他的父親病了，他有責任照顧他。