A. attempt B. charged C. crucial D. delicate E. essentially F. eventually

游客2023-10-25 64

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. [br] 【C2】

选项

答案 C

解析空格前为不定冠词a，空格后为名词step，因此，空格处应填入一个形容词作定语修饰step。空格后提到，将人类送上火星是一个梦想，因此，能够成功地发射可重复使用的火箭是朝着这个梦想迈出的关键一步，故C项crucial“至关重要的，关键性的”为答案。

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