Question

The vast majority of us spend our entire lives pulled down by gravity. Then there are astronauts.

This small population of space travelers has given researchers a rare look at what happens to the human body when it’s able to spend large amounts of time outside the downward pull of the Earth. This week, a study on one of the largest groups of astronauts yet ---34 participants---was published in The New England Journal of Medicine.

In the new study, a team of international radiologists supported by NASA looked at MRIs of the brains of astronauts before and after their trips to space. The scientists found that upon returning to Earth, many of the astronauts’ brains had become repositioned inside their skulls, floating higher than before. In addition, the space between certain brain areas appeared to have shrunk. The changes were more common in astronauts who took longer trips into space.

The team characterized astronaut trips as short (an average of less than 14 days) or long (an average of about 165 days). Radiologists who didn't know each astronaut's duration（持续时间）in space compared MRIs from before and after their trips.

Of the 34 total astronauts involved in the study, 18 took long trips to space—spending most of that time on the International Space Station —and of those, 17 returned to Earth with smaller areas between the frontal lobe（脑前额叶）and parietal lobe（顶叶）. The same area of the brain also shrank for three of the 16 astronauts who took shorter trips with the US Space Shuttle Program. The researchers also found that 12 of the ISS astronauts and six of the space-shuttle astronauts returned home with their brains sitting slightly higher in their skulls than before.

It’s not clear what, if anything, these brain changes mean for the health of space travelers. In general, it appears the human body tolerates space travel fairly well: the time astronauts have spent in zero-gravity environments so far doesn’t seem to have had any strong or long-lasting effects.

1.What is the finding of the study?

A. Astronauts have great brain power.

B. Astronauts’ duration in space is updated.

C. Astronauts’ skulls expand after space trips.

D. Astronauts return to Earth with raised brains.

2.How did the scientists draw the conclusion?

A. By analyzing astronauts’ symptoms.

B. By comparing each astronaut’s MRIs.

C. By monitoring astronauts’ brain activities.

D. By observing countless astronauts’ behaviors.

3.What does the author say about the changes inside astronauts’ skulls?

A. They are totally harmless.

B. Their effects are hard to assess.

C. Their occurrence is unavoidable.

D. They will heavily influence astronauts.

4.What is the best title for the text?

A. Effects of zero gravity

B. Valuable experiences of space travel

C. Space travel changes astronauts’ brains

D. Flying long house increases health risks

Answer

1.D

2.B

3.B

4.C

【解析】本文是一篇科普类说明文。本文主要讲了科学家通过分析一群宇航员在太空旅行前后的大脑核磁共振成像，发现宇航员经过太空旅行后，大脑的位置会升高。

1.细节理解题。由第三段The scientists found that upon returning to Earth, many of the astronauts’ brains had become repositioned inside their skulls, floating higher than before.可知，这项研究结果表明宇航员返回地球，大脑的位置会升高，选D。

2.细节理解题。由第五段Radiologists who didn't know each astronaut's duration（持续时间）in space compared MRIs from before and after their trips.可知，科学家通过比较每位宇航员的核磁共振成像得出结论，选B。

3.细节理解题。由最后一段It’s not clear what, if anything, these brain changes mean for the health of space travelers.可知，对于宇航员头脑内部的改变，它们对健康的影响，很难评估，选B。

4.主旨大意题。通过阅读文章可知，这篇文章主要讲了科学家通过分析一群宇航员在太空旅行前后的大脑核磁共振成像，发现宇航员经过太空旅行后，脑部的位置会上升，故C项为最佳标题。