单项选择题
A．monitor the hours of doctors by themselves B．make sure that the doctors who treat them have had enough sleep C．ask for legal control of the hours of doctors D．allow their doctors to sleep several hours before the operation
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