A. attempt B. charged C. crucial D. delicate E. essentially F. eventually G. expended H. fraction I. individual J. maintain

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问题    A. attempt B. charged C. crucial D. delicate E. essentially
   F. eventually G. expended H. fraction I. individual J. maintain
   K. minority L. negligible M. scrapping N. slashing O. upsurging
   Space X launched a cheaper, partially-used rocket into orbit. That’s a stride toward 【C1】______the price tag of sending payload to space. Successfully flying reusable rockets is a 【C2】______step toward the dream of sending people to Mars. Until now, rockets have almost all been single-use. Once the fuel is【C3】______, a rocket stage plummets to Earth, resulting in the destruction of extremely expensive equipment that costs tens of millions of dollars to build.
   Its founder has likened that to 【C4】______a 747 jet after one flight, which would make air travel impossibly expensive. He has suggested that rocket launches could 【C5】______be much cheaper since the cost of the rocket propellants are less than 1 percent of the full-price ticket for a launch. So, if a rocket could be simply refueled like a jetliner for another flight, the cost of space travel could drop to a 【C6】______of what it is now. The stresses of spaceflight on reused boosters, however, are much greater than those on jetliners. The economics will depend on how many times a booster can be flown, and how much the 【C7】______expense will be to repair the booster each time.
   Reusable spaceships are not a new idea. NASA’s space shuttles were the first real 【C8】______at a reusable spaceship, but the shuttles proved more 【C9】______than hoped, requiring an army of technicians to 【C10】______them between flights. As a result, they ended up being more expensive than expendable rockets.
【C3】

选项

答案G

解析 空格前是系动词is,分析句子结构可知,once引导时间状语从句,因此,空格处应填入一个形容词构成系表结构,或填入一个现在分词或过去分词构成进行时态或被动语态。空格前面一句提到,在此之前的火箭几乎都是单次使用的。再结合常识可知,一旦火箭耗尽了燃料,它就会坠回地球,故G项expended“花费,耗费”为答案。
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