back duty

例句：

1. 1. The company's back duty is to ensure the smoothoperation of their operations.
   公司的后勤工作是确保其运营的顺利进行。
2. 2. The backduty of a soldier is to protect hiscomrades and defend the country.
   士兵的后勤职责是保护战友并保卫国家。
3. 3. The back duty of a doctoris to provide medical care for patients inneed.
   医生的后勤职责是为需要医疗的患者提供医疗服务。