the line of duty

例句：

1. 1. He wasassigned to the line of duty as apolice officer.
   他被分配为一名警官，担任职责。
2. 2. The captain's line ofduty is to ensure the safety of allon board.
   船长的职责是确保船上所有人的安全。
3. 3. She took on the line of dutywhen her husband passed away.
   当她的丈夫去世后，她承担了职责。