您要查找的是不是：
- No lifeguard on duty. 没有救生员。”
- Yes. We usually have two lifeguards on duty. 有，通常有两位救生员值班。
- Is there a lifeguard on duty? 有当班的救生员吗?
- Half the garrison is/are on duty. 有半数卫戍部队在执勤。
- Please bleep the doctor on duty immediately. 请立刻用传呼机召值班医生。
- We have lifeguards on duty. 我们有救生员值班。
- The rule is that someone must be on duty at all times. 按照规定，任何时候均需有人值班。
- He reported the murder to the police on duty. 他将凶杀事件告知值班警察。
- The police on duty rode the escaping thief down. 值班警察追上了逃跑的小偷。
- I arrive at the hospital at eight o'clock, but I don't go on duty until nine. 我八点钟就到医院了，但是九点钟我才去值班。
- Fear of drowning will keep a swimmer from swimming in the ocean if there is no lifeguard around. 要是周围没有救生人员，游泳者就不敢到海里游泳，怕淹死。
- I'm on duty as from the Spring Day. 我刚好在春节那天值日。
- Two retired workers are on duty guarding the gate. 两个退休工人值班守卫大门。
- We come on duty seven hours a day. 我们每天上班七小时。
- He is on duty from 9 a.m. to 6 p.m. today. 他今天从早晨9点到下午6点值班。
- Who will be on duty at six o'clock? ---I will. 6点钟谁值班?-我值班。
- A policeman is not allowed to smoke on duty. 警察值班时不准吸烟。
- I had lifted my hand against a pilot on duty. 我打了一个值班的掌舵。
- Experienced banquet waiters must also be on duty. 还必须让有经验的宴会服务员当班。
- I am on duty tomorrow. I'll have to switch with someone to go to your party. 我明天值班。我得和谁换一下班才能去参加你们的聚会。
