1. There were over 200 police on duty.

2. I am on duty today.

3. Half the garrison is / are on duty.

4. The nurse on duty was fearful that the patient should get worse.

5. There were two security guards on duty outside the building.

6. The rule is that someone must be on duty at all times.

7. There were over 100 police on duty at the demonstration.

8. The man on duty rang an alarm.

9. You're not allowed to drink alcohol on duty.

9. Sentencedict.com is a sentence dictionary, on which you can find excellent sentences for a large number of words.

10. Half the garrison are on duty.

11. Please bleep the doctor on duty immediately.

12. She goes on duty in half an hour.

13. Mary goes on duty tonight at half past ten.

14. Extra staff had been put on duty.

15. The policeman was gunned down while on duty.

16. He was on duty and in uniform.

17. The night watch comes on duty soon.

18. I was on duty morning, noon(sentencedict.com), and night.

19. The officers on duty were visibly overcome, many of them in tears.

20. The teachers on duty are policing the school buildings during the lunch hour.

21. I'm on duty until 2 p.m. and then Peter is coming to relieve me.

22. There will only be a skeleton staff on duty over the holiday.

23. I'll be on duty from 8 am to 10 pm.

24. Eight are on duty.

25. The patrol police on duty are on the alert against any possible disturbances.

26. The striped band round a policeman's sleeve is to signify that he is on duty.

27. It was Mrs Dearden's day off, and Paul was on duty in her place.

28. A policeman has to keep on his toes all the time he's on duty.

29. A promise was given to double the number of police on duty.

30. In addition to these arrangements, extra ambulances will be on duty until midnight.