单项选择题
A．the tide was not suitable B．she had run aground on sand C．her engines had broken down D．most of her crew had gone ashore
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