单选题 Aristotle believed that the heavens were perfect. If they ever were, they are no longer. The skies above Earth are now littered with the debris (残骸) of dead satellites, bits of old rockets and the odd tool dropped by a spacewalking astronaut. Such is the extent of the detritus that the first accidental collision between two satellites has already taken place. It happened in February 2009, when a defunct (废弃的) Russian Cosmos smashed into a functioning American Iridium, destroying both and creating even more space junk.
To stop this sort of thing happening again Vaios Lappas of the University of Surrey, in England, has designed a system that will remove satellites from orbit at the end of their useful lives--and as a bonus will scour part of the sky clean as it does so. Dr. Lappas's satellite-removal system employs a solar sail. As light from the sun hits the sail, it imparts a minuscule but continuous acceleration. When a satellite is first launched, the sail is angled in a way that causes this acceleration to keep the satellite in orbit. (Orbits gradually decay as a result of collisions with the small number of air molecules found even at altitudes normally classified as "outer space". )
Solar sails have yet to be used widely to propel spacecraft in this way--several earlier versions came unstuck when the sails failed to unfurl properly-but doing so is not a novel idea in principle The novelty Dr. Lappas envisages is to change the angle of the sail when the satellite has become defunct. Instead of keeping the derelict craft in orbit, it will, over the course of a couple of years, drag it into the atmosphere and thus to a fiery end. Not only that, but the sail will also act like a handkerchief, mopping up microscopic orbital detritus such as flecks of paint from previous launches. A fleck of paint may not sound dangerous, but if travelling at 27 000kph (17 000mph), as it would be in orbit, it could easily penetrate an astronaut's spacesuit.
A prototype of Dr. Lappas's design, called CubeSail, will be launched late next year. It weighs just 3kg and, when folded up, measures 30cm (12 inches) by 10era by 10era. Once unfurled, however, the sail will have an area of 25 square metres. If this prototype, which is paid for by EADS, a European aerospace company, proves successful, solar sails might be added to many future satellites. That would enable them to be removed rapidly from orbit when they became useless and would restore to the skies some measure of Aristotelian perfection.

单选题 The first sentence in this passage is to ______.
[A] criticize Aristotle's viewpoint [B] praise the beauty of the outer space
[C] express Aristotle's attitude towards the heavens [D] warn that the space is now littered with junk

【正确答案】 D

【答案解析】[解题思路] 本题考查对文章首句用意的理解，需要从下文中找出答案。文章接下来陈述现在太空中充满了垃圾的事实。因此作者带有警示之意，告诫人们要保护太空环境，故[D]正确。第二句提到，即使它们曾经很洁净，现在也不复存在了，有一种惋惜之意，作者并没有赞美太空之意，故排除[B]。[A]和[C]都只停留在表面，作者是想通过亚里士多德的观点引出太空垃圾的话题，故不正确。

单选题 Which one is NOT the application of the system designed by Vaios Lappas?
[A] To halt creating more space junk. [B] To remove the satellites at the end of their useful lives.
[C] To stop the accidental collisions in space. [D] To clean the junk created by dead satellites.

【正确答案】 C

【答案解析】[解题思路] 文章第二段讲述拉帕斯设计的系统的应用情况。第一句中that引导的定语从句对system进行了解释说明，即能在卫星完成使命后将其从轨道中清除，[B]是对该意思的同义转述。第一句破折号后提到这个系统还有一个附带作用，就是能够清洁天空，也就是清扫太空垃圾的作用，[A]和[D]谈到的就是此作用。通过排除法可知，[C]不是这个系统的作用，也不是拉帕斯发明此系统的用意，故为正确答案。

单选题 Orbits decay due to ______.
[A] the acceleration of the spacecraft [B] the crash with small amounts of air molecules
[C] the invention and application of solar sails [D] the existence of air molecules

【正确答案】 B

【答案解析】[解题思路] 本题考查轨道渐渐衰减的原因。第二段括号中as a result of引出了其原因，即与为数甚少的空气分子相互碰撞所致，只有[B]陈述的是与微粒碰撞，符合题意。第二段倒数第一句谈到加速是为了把卫星保持在轨道之上，并非轨道衰减的原因，故[A]理解有误。从第二段第三、四句可以看出，太阳能帆板的作用是给卫星加速，所以[C]不正确。[D]属于断章取义，空气分子的存在只是轨道衰减的一个前提条件，并不是充分条件，必须碰撞才会使轨道逐渐衰减。

单选题 If the CubeSail turns to be practical, the design will ______.
[A] be granted a patent to reward Dr. Lappas
[B] make our skies return to be perfect
[C] be still useless to remove the satellites from orbit
[D] be applied to all the future satellites

【正确答案】 B

【答案解析】[解题思路] 本题考查立方体太阳能帆板模型试用成功的实际意义。文章最后提到，这些卫星使命完成时，可以迅速从轨道中清除，天空就会慢慢回归亚里士多德时期的完美无瑕。由此可见该设计的最终目的还是为了使天空更洁净，所以[B]为正确答案。[A]文章没有提及。文中最后一句提到当这些卫星没有用途时，它们就会被迅速从轨道中清除，而不是对清除卫星没作用，[C]是对该意思的误解。文中倒数第二句提到，该模型一经试用成功就会应用于很多未来发射的卫星，并没有说应用于所有卫星，所以[D]也不正确。