Plastic magazines are sometimes partially transparent so the operator can easily check the remaining ammunition.

The operator checked, and gave him a number.

The operators could check on them for disease with minimum effort.

I would call, the operator would check my name on the computer, and she would say, "No, nothing."

Nevertheless the regular operator carefully checked over his uranium detection station.

The operator must also check that all trains are in correct position or else the lift chain will not restart.

Next, the operator should check the diamond saw blade.

One operator checked the oil as he was supposed to do, saw the shortage, thought it odd, said nothing, and added four quarts.

The other operator had checked his the afternoon before, as was his habit.

Then the operators must check that none of their main systems have suffered any structural damage before firing them back up.