on duty
US /ˈɑn ˈduː.ti/
UK /ˈɒn ˈdjuː.ti/
短语
值班, 在岗
working, especially when one is a police officer, a soldier, or a medical worker
示例:
•
The police officer was on duty for twelve hours.
这名警察值班了十二个小时。
•
Nurses are always on duty, even on holidays.
护士们总是值班，即使在节假日也是如此。