单项选择题
A．fallen asleep B．drunk too much C．been driving too long D．avoided hitting parked cars
A．they are too tired to fall asleep B．they are forbidden to sleep at work C．they are kept by treating their patients D．they are too worried about oversleeping
A．can still provide quality medical care B．will remain alert because he is used to it C．may ignore the potential risk of insufficient sleep D．should be fired if he continues the medical operation