阅读理解

Can you imagine astronauts' everyday life in space?

On Earth, we put food on a plate because there's gravity on our Earth. But there's almost no gravity in space，so food can float away，and astronauts must eat carefully.

Sleeping is very different in space. Some astronauts like to float in the air，but most like to be in a sleeping bag. They tie the bag to a wall that they won't float away.

Exercise is very important in space. In space，astronauts do not use their legs often. This is bad for their legs，so they must do exercise for thirty minutes everyday.