Mars(火星)is the fourth planet from the Sun and the second smallest planet in the Solar System.
Is there life on Mars? Nobody knows. We are sure that people cannot live on Mars so far. We need oxygen to live. But there is almost no oxygen on Mars.
Living on Mars is like living on a very high mountain. There is little air. It can be as hot as about 50℃ above zero at noon and as cold as about 100℃ below zero at night.
Plants and animals can grow on the Earth because it has a lot of carbon (碳). Like the Earth, Mars has this kind of material as well. So many people think there may be plants on Mars. And it has four different seasons. Of all the planets in the Solar System, the seasons of Mars are the most Earth-like.
Through a telescope, we see that Mars looks red. In some places, it seems grey. Sometimes, grey colour turns grey-green, then brown, then grey again. The grey-green colour may be a kind of plant life. It changes colour with the seasons.
Will people go to Mars one day? If they do, they will have to take along with them their own oxygen, food, clothing, something to sleep in and so on.
51.Which may be the temperature on Mars at night?
A.-150°C.
B.50°C.
C.-100°C.
D.100°C.
52. Why many people think there may be plants on Mars?
A. Because Mars has carbon.
B. Because Mars has a lot of air.
C. Because the temperature on Mars is good for plants.
D. Because the seasons of Mars are just the same as the Earth's.
53. through a telescope, how many colours can you find on Mars?
A. 2.
B. 3.
C. 4.
D. 5.
54. according to the passage, which of the following is TRUE?
A. Mars is the smallest planet in the Solar System.
B. There is enough oxygen on Mars for people.
C. Mars changes its colour with different seasons.
D. There may be life on Mars.
55.From the last paragraph, what can we know?
A. People would like to live on Mars.
B. It will be quite hard for people to live on Mars.
C. People will not take water to Mars.
D. Mars is a better place for people to live on.
答案及解析：
51. C. -100°C.
解析：根据文章中的描述，火星夜晚的温度可以降到零下100度(as cold as about 100℃ below zero at night)，因此选项C是正确的。
52. A. Because Mars has carbon.
解析：文章提到地球上的植物和动物能够生长是因为有大量的碳，火星上也有这种物质，所以许多人认为火星上可能有植物(Like the Earth, Mars has this kind of material as well. So many people think there may be plants on Mars.)。
53. C. 4.
解析：文章中提到通过望远镜观察火星，火星看起来是红色的，有些地方看起来是灰色的，灰色有时会变成灰绿色，然后是棕色，再变回灰色。因此，我们可以找到红色、灰色、灰绿色、棕色四种颜色。
54. C. Mars changes its colour with different seasons.
解析：文章中提到火星的颜色会随着季节的变化而变化(It changes colour with the seasons)，这与选项C相符。
55. B. It will be quite hard for people to live on Mars.
解析：文章最后一段提到，如果人们要去火星，他们将不得不带上自己的氧气、食物、衣服、睡觉的东西等等，这表明在火星上生活将会非常困难。
