单项选择题
A．makes a bed B．gets into his bag C．listens to music D．wears a sleep mask
A．They have to follow the same timetable. B．The radio will take care of the aircraft for them. C．There are enough sleeping bags in the spacecraft. D．There is no need for them to watch over the spacecraft.
A．on the wall B．to their seats C．onto the flight deck D．anywhere they like