Staff members are on call for a week at a time.

But the days of being on call 24 hours a day are over.

The next three days she will be on call 24 hours a day.

He would be on call for the other 156 hours.

I just didn't want to be on call to everybody.

And as he did so, what had not come on call came of itself.

He is on call 24 hours a day, seven days a week.

"I just looked up a few things before coming along on the call."

But you can ask two questions about your wife on the same call.

One doctor on call come to the college for student health care.