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  3. Aristotle believed that the heavens were perfect. If they ever were, they are no longer. The skies above Earth are now littered

Aristotle believed that the heavens were perfect. If they ever were, they are no longer. The skies above Earth are now littered

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问题     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.
The first sentence in this passage is to ______.
选项 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
答案D
解析 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。  
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