for a long time
131for hours on end — {adv. phr.} For many hours; for a very long time. * /We have been trying to get this computer going for hours on end, but we need serious professional help./ …
132for hours on end — {adv. phr.} For many hours; for a very long time. * /We have been trying to get this computer going for hours on end, but we need serious professional help./ …