首页
登录
职称英语
Someday, in【C1】______ the outer planets of our solar system, humankind wil
Someday, in【C1】______ the outer planets of our solar system, humankind wil
游客
2024-05-05
4
管理
问题
Someday, in【C1】______ the outer planets of our solar system, humankind will want to do【C2】______ send small probes that merely fly rapidly by them. In time, we will want【C3】______ spacecraft that will go【C4】______ orbit around these alien planets, land robots on their moons, and even return rock and soil sample back to Earth.【C5】______ , we will want to send humans to their moons, on at least【C6】______ which liquid water—the fundamental requirementfor life【C7】______ we know it—is believed to be【C8】______ .
For missions such as these, we will need rockets powered by a nuclear reaction【C9】______ igniting chemicals. Chemical rockets have served us well. But the【C10】______ low amount of energy that they can deliver for a given mass of fuel is a severe【C11】______ when dispatching spacecraft【C12】______ long distances. To reach the outer planets, for example, a chemically-powered space vehicle must【C13】______ fuel by having a very small mass and making【C14】______ use of gravity "assists", in which the craft maneuvers close enough to a planet for the planet’s gravity to propel the craft forward,【C15】______ its speed.
In technical term, chemical rockets have low【C16】______ velocity growth, which means that their exhaust velocities are not high enough to【C17】______ very high speed to the rocket. Nuclear rockets,【C18】______ their chemical counterparts, could impart a maximum velocity of【C19】______ about 22 kilometers a second. Such a high velocity would make possible a direct path to Saturn (土星), reducing travel time from about seven years to as【C20】______ as three. [br] 【C14】
选项
A、exclusive
B、extensive
C、plentiful
D、intensive
答案
B
解析
形容词辨义题。本处意思是:并充分利用引力的“帮助”来节省燃料。选项中只有extensive可以修饰use,故选B extensive“广泛的”。
转载请注明原文地址:https://tihaiku.com/zcyy/3585595.html
相关试题推荐
Someday,in【C1】______theouterplanetsofoursolarsystem,humankindwil
Someday,in【C1】______theouterplanetsofoursolarsystem,humankindwil
Someday,in【C1】______theouterplanetsofoursolarsystem,humankindwil
Someday,in【C1】______theouterplanetsofoursolarsystem,humankindwil
Someday,in【C1】______theouterplanetsofoursolarsystem,humankindwil
Someday,in【C1】______theouterplanetsofoursolarsystem,humankindwil
Someday,in【C1】______theouterplanetsofoursolarsystem,humankindwil
Someday,in【C1】______theouterplanetsofoursolarsystem,humankindwil
Someday,in【C1】______theouterplanetsofoursolarsystem,humankindwil
Someday,in【C1】______theouterplanetsofoursolarsystem,humankindwil
随机试题
中国园林几个世纪以来,中国在自然中寻求灵感和自我认知。因此,中国园林倡导回归自然世界。由于城市
Whatisthepassagemainlyconcernedwith?[br]Theword"unwieldy"inthesecon
HowAdvertisementIsDone?A)Whenwechooseawordwedomorethangive
固体分散物的载体材料对药物溶出的促进作用包括A.载体材料对药物有抑晶性 B.水
根据《建设工程施工合同(示范文本)》GF-2017-0201,合同文本由()
A.2%~4%碳酸氢钠溶液 B.温水或生理盐水 C.3%过氧化氢溶液 D.
2011年国内生产总值为()亿元。 A.469793.8 B.42368
“四五运动”最重要的意义在于 A.控诉“四人帮”的罪恶 B.沉痛悼念周恩来总
江南一带的山水,一方面是坡势平缓的丘陵山地,水波不兴的江河湖泊,另一方面茂林修竹
王某因追索工资与所在公司发生争议,遂向某法律工作者咨询。该法律工作者的下列观点中
最新回复
(
0
)