How to use in-sentence of “on duty”:
+ Initially the ring of steel consisted of plastic cones and on duty policemen which the locals described as the ‘ring of plastic’.
+ While in the army, his officers said that he was often caught sleeping on duty and needed to be watched at all times.
+ The DDR border guards did not do anything either; neither did the United States personnel on duty at the Checkpoint.
+ In major incidents, most hospitals have protocols to have staff that are not at work at the hospital to go on duty as fast as they can.
+ There will also be beds, for when they are on duty at night.
