How many days is Mr. Robertson going to stay in Beijing

A．offered to help without knowing what to do
B．did not want to put themselves in any danger
C．realized the trouble but could do nothing about it
D．did not know there was something wrong with the ship

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