《2025年同步练习册配套检测卷九年级英语上册鲁教版五四制》

B
Many people dream of travelling into outer space. However, spending too much time in space may cause health problems, according to NASA. That's why astronauts shouldn't spend more than six months on the International Space Station (ISS) at a time.
Muscle (肌肉) and boneless
In a weightless environment, astronauts don't need to use their muscles to support themselves. Therefore, their muscles start shrinking (萎缩). To keep their muscles strong, astronauts need to exercise about 2 hours each day on the ISS. The weightless environment also causes astronauts bones to lose minerals (矿物质), with density (密度) dropping at over 1 percent per month. The rate of bone loss for elderly people on Earth is 1 to 1.5 percent per year.
Sleep disorder (混乱)
In space, the sun rises every 90 minutes. It is hard for astronauts to get used to this light-dark cycle when they sleep. Also, they need to sleep in a sleeping bag that is fixed to a wall, which is uncomfortable. Astronauts now have individual sleeping pods (分离仓) that help shut out some of the light. Still, studies have found that most astronauts only sleep about six hours each night, even though they should have eight and a half hours.
Brain changes
Scientists have found that the position of the brain changes during spaceflight. It shifts upward within the skull (头骨). This can affect how the brain deals with how we see, stay balanced and move around.
That's why some astronauts can't control their movement and balance after returning to the earth. Scientists have also found that astronauts may get used to this change after going on more spaceflights. But they still need to do more research.
(C)
4. Astronauts suffer muscle problems after returning to the earth because ______.
A. they are too busy to exercise in space
B. they don't have enough room to exercise in space
C. they don't use their muscles in space
D. they rarely walk while in space
(A)
5. Astronauts sleep in individual sleeping pods to ______.
A. shut out light
B. stay warm at night
C. enjoy a quiet atmosphere
D. prevent themselves from floating around
(B)
6. How can astronauts deal with the problem of losing their balance?
A. They can walk upside-down on the earth.
B. They can go on more spaceflights.
C. They can take some medicine.
D. They can sleep more and rest.
(B)
7. What's the best title for this passage?
A. Dream of travelling into space
B. Health problems in space
C. Muscle and bone loss in space
D. Astronauts in space

答案： 4. C
5. A
6. B
7. B