phrase Someone who is on assignment is doing a particular job or piece of work, usually in a particular place where they have been sent for a period of time: 执行任务;（通常指被派遣到特定地点从事一段时间的）工作 Both journalists were killed while on assignment in the region. He was on assignment for the New Yorker, where he was a photographer. Her husband, a helicopter pilot, had been on assignment in Iraq for over seven months. She told people she was in the area on assignment. He was suffering from a disease he contracted while on assignment in Panama. See also
assignment
on assignment | American Dictionary
on assignment
idiom doing a job, especially a job in which you are reporting news for a newspaper, television station, etc.: The two journalists met while on assignment in Colombia.