Is it possible to live on other planets? The United States government is taking a serious look at the moon and Mars as potential places for future human settlement. The moon could serve as a training ground for later journeys to Mars. Currently, with Mars becoming the eventual long-term goal, serious questions exist as to whether the dangers of the settlement on the moon are too extreme and unnecessary.

One major reason the settlement on the moon is too dangerous is the difference between the atmosphere environment of the moon and Mars. Atmosphere is important because it protects humans and all other life from a continuous attack of radiation (辐射) caused by sources such as the sun. This radiation is especially dangerous to humans because it increases the risk of cancer and can negatively change DNA. The fact that the moon has no atmosphere can cause great harm to human beings. Although Mars’ atmosphere is significantly thinner than Earth’s, at least it has one and would create some sort of protective barrier for humans.

Another important characteristic necessary for human settlement is natural resources like water, of which the moon is believed to have none. Mars, however, contains vast quantities of water ice, dry ice, and also snow. There is also sufficient evidence that water once existed at the surface of Mars and might return in the future if the planet warms. With increased technologies, the potential for settlers to remain on Mars by being increasingly self-sufficient makes Mars a much more attractive goal as the space settlement than the moon.

Future settlers will not only benefit from potential water on Mars; the planet is also rich in other natural resources such as oxygen, hydrogen, and minerals, which can be well used in productive ways. For example, hydrogen can be used as fuel, and it can be combined with nitrogen (氮气) to form new materials necessary for human settlement. Due to these advantages,

Mars would be a more successful planet for exploration and settlement because it contains the basic resources necessary for humans to survive.

Since the environment of Mars is more similar to that of Earth and it contains resources necessary to help life exist, it should be the only option for any kind of long-term human settlement. The settlement on Mars would not only be a milestone in space but also an excellent chance for mankind to improve itself from past adventures on Earth and preserve and make the best use of the natural resources Mars has to offer.

【1】According to Paragraph 2, the atmosphere on Mars would .

A. change the DNA structure of humans

B. measure the harmful radiation from space

C. provide protection against dangerous effects

D. cause humans to be exposed to serious illnesses

【2】What can be inferred about water on Mars?

A. It is not present in a liquid state.

B. It doesn’t exist in large quantities.

C. It will bring potential dangers to settlers.

D. It can be easily changed into liquid forms.

【3】The author believes that .

A. exploration of Mars takes great risk

B. natural resources on Mars last forever

C. settlement on Mars is perfectly acceptable

D. Mars is more suitable for settlement than Earth

【4】Which of the following shows the development of ideas in the passage?

CP: Central Point P: Point Sp: Sub-point (次要点) C: Conclusion

A. B.

C. D.

【答案】

【1】 C

【2】 A

【3】 C

【4】 B

【解析】

这是一篇说明文。介绍了火星为什么是人类的新定居点。

【1】细节理解题。由第二段“Although Mars’ atmosphere is significantly thinner than Earth’s, at least it has one and would create some sort of protective barrier for humans”可知，尽管火星的大气层比地球的要稀薄得多，但至少火星有大气，这会给人类创造某种保护屏障。所以根据第二段，火星的大气保护人们免受辐射对人们的危害。故C选项正确。

【2】推理判断题。由第三段“however, contains vast quantities of water ice, dry ice, and also snow.”可知，然而，火星上有大量的水冰、干冰和雪。所以判断出，火星上的冰不以液态存在。故A选项正确。

【3】细节理解题。由全文尤其是第五段“Mars would be a more successful planet for exploration and settlement because it contains the basic resources necessary for humans to survive.”可知，全文都在介绍为什么火星是上人类的新定居点的因素，所以作者认为火星对于探索和定居，是非常适合人类的星球，定居是完全可以接受的，因为它包含了人类生存所必需的基本资源。故C选项正确。

【4】推理判断题。通读全文可知，短文是围绕这中心点“火星为什么是人类的新定居点”。中心论点包括两个方面。第一，通过火星和月球的对比说明火星上能够适应人类定居。并通过两个次要段落，次要点来支持论点。1.对比火星上和月球上的大气来说明火星适应人类定居。2.对比火星上和月球上的水来说明火星适应人类定居。第二，通过火星上存在的资源来说明火影上能够适应人类定居。最后是总结段落。所以我们判断出短文是按照B选项发展的。故B选项正确。