单项选择题
The best title for this passage is（）
A．Traveling in Space B．Sleeping in the Spacecraft C．Equipment Used by Astronauts D．The Earth Seen from Outer Space
单项选择题 How long does it take the spacecraft to go round the Earth（）
单项选择题 To relax himself before sleep, the writer often（）
单项选择题 Why can all the astronauts sleep at the same time（）
