Question

    In space, there is no up or down. Without the gravity that we experience on Earth, as-tronauts and everything else on a spaceship float freely.

Humans can experience the sense of zero gravity without going into space. How？A zero-gravity flight. When an airplane flies in a lot of parabolas（抛物线）, a man-made zero-gravity environment is set up. Everything in the plane floats, even passengers.

Gravity has an effect on everything from the human body and mind to the behavior of plants and the way machines run. Space travel is expensive and dangerous. But zero-gravity flights let scientists conduct experiments in an environment that mimics（模拟） the conditions of space. On each of its research trip, Zero-G flies about 30 parabolas, each of which creates a period of weightlessness that lasts about 30 seconds. Nikolaus Kuhn of the University of Ba-sel, in Switzerland, flew with Zero-G. He was conducting an experiment about soil and the flow of water on Mars. The Red Planet has about one-third of the gravity that Earth has. This means water flows more slowly on Mars. By making the parabolas less steep, zero-gravity flights can make the feeling of Martian gravity. Flying with Zero-G has been necessary for Kuhn’s research. “It is the only chance, other than going to Mars, to mimic movement of water as it would be on Mars,” he told TFK.

For years, NASA used zero-gravity flights to prepare and train astronauts. “I have not been to space,” Peters of Zero-G says, “But I have been told by astronauts that zero-gravity feels exactly the same.” As humans continue to explore the universe beyond Planet Earth, zero-gravity flights will remain an important and fun tool. “It never gets old,” Peters says “I would do it every weekend for the rest of my life if I could.”

1.Why do scientists set up man-made zero-gravity environment？

A.To study the water on the earth.

B.To offer weightlessness as a business.

C.To take scientists to any other planets.

D.To mimic the condition of space for experiments.

2.How much time of weightlessness can a Zero-G light offer？

A.About 30 seconds. B.About 90 seconds.

C.About 15 minutes. D.About 30 minutes.

3.What feature do the parabolas in Zero-G flights have？

A.The gentler parabolas are, the more satisfied the researchers are.

B.The steeper parabolas are, the less weight the passengers feel.

C.The steeper parabolas are, the more successful the experiments are.

D.The gentler parabolas are, the more quickly water on Mars flows.

4.What can be inferred about the Zero-G flight from the text？

A.It is useless for training astronauts.

B.It has no side effect on human body.

C.It creates a substitutable environment of zero gravity in space.

D.It is cheaper but more dangerous than space travel.

Answer

1.D

2.C

3.B

4.C

【解析】

这是一篇说明文。文章主要介绍了什么是失重飞行以及失重飞行的原理及作用。

1.

细节理解题。根据文章第三段句子“But zero-gravity flights let scientists conduct experiments in an environment that mimics（模拟） the conditions of space.”可知，失重飞行能够模拟太空零重力的环境，便于科学家组织实验。由此可知，科学家要建立人造的零重力环境是为了模拟空间条件进行实验。故选D项。

2.

细节理解题。根据文章第三段句子“On each of its research trip, Zero-G flies about 30 parabolas, each of which creates a period of weightlessness that lasts about 30 seconds.”可知，每次研究之旅中，失重飞行约30条抛物线，每条抛物线创造了约30秒的失重时间。也就是说约30条抛物线共创造了约900秒的失重时间，合计约15分钟。故选C项。

3.

细节理解题。根据文章第三段句子“The Red Planet has about one-third of the gravity that Earth has.”可知，火星上的重力约为地球的三分之一。再根据第三段句子“By making the parabolas less steep, zero-gravity flights can make the feeling of Martian gravity.”可知，通过使抛物线不那么陡峭，失重飞行就能让人感受到火星的重力。即抛物线越陡，乘客感受到的重量就越轻。故选B项。

4.

细节理解题。根据文章第二段句子“A zero-gravity flight. When an airplane flies in a lot of parabolas（抛物线）, a man-made zero-gravity environment is set up. ”可知，失重飞行能够创造一个环境，这个环境可以替代太空中的失重环境。故选C项。