首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
外语
Someday, in【C1】______ the outer planets of our solar system, humankind will want to do【C2】______ send small probes that merely
Someday, in【C1】______ the outer planets of our solar system, humankind will want to do【C2】______ send small probes that merely
admin
2013-06-02
22
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.
【C16】
选项
A、maximum
B、minimum
C、massive
D、efficient
答案
A
解析
形容词辨义题。本处意思是:化学燃料推动的火箭(从起步)到达最快速度的增速很慢。故选 A maximum“最大的,最高的”。
转载请注明原文地址:https://jikaoti.com/ti/k8bFFFFM
0
大学英语六级
相关试题推荐
A、Bycombiningvariouschemicalcomponents.B、Bychangingthecombinationofgunpowder.C、Bymixingdifferenttypesofgunpowder
Fromthechildtooldage,wealluselanguageasameansof【B1】______ourknowledgeofourselvesandtheworldaroundus.When
TheAmericanideaofrespectinghumanrightscamefromseveralsources.First,thecolonistshadbeen【36】oftheirfightsinthe
A、Radiationfromtheterminal.B、Stressinworkinghours.C、Withoutadequateeye-drops.D、Lessorlittlemoistureintheeyes.D
Scotlandisauniqueplace.IthassomeofthemostbeautifulcitiesinEurope,alivingevidenceofasplendidandproudpast.
A、Stonejewelry,B、Beautifulstone.C、Artsandcrafts.D、Amazingpaintings.C信息明示题。男士说自己去镇上的印第安市场买工艺品,故选C。男士提到自己遇到了一位神奇的老妇人,她卖的石
Largecompaniesneedawaytoreachthesavingsofthepublicatlarge.Thesameproblem,onasmalle【B1】______facespracticall
EndYourBackPainLikeanexpensivebuttemperamentalsportscar,thehumanspinisbeautifullydesignedandmaddeninglyu
A、Onlyone.B、Two.C、Three.D、Morethanthree.A
A、NewEngland.B、Britain.C、Newfoundland.D、Alaska.C
随机试题
间接抗球蛋白试验检测何类抗体
(2006年)测量工作的基准线是()。
个人商用房贷款期限最长不超过()年。
国家助学贷款一般在()内还清。
把秋季集中产出的大米储存起来,起到稳定大米价格的功效,这是仓储的()。
公安机关对发现或者受理的案件暂时无法确定为刑事案件或者行政案件的,必须先按照刑事案件的程序办理。()
智力是创造力的充要条件。(2010年)
Facebookhasbeen【C1】______withfireandhasgotitsfingersburned,again.OnNovember29thAmerica’sFederalTradeCommission
WWW的超链接中定位信息所在位置使用的是______。
A、Tokeepfit.B、Tostudywell.C、Toearnmoremoney.D、Togainesteem.A事实细节题。短文开头提到,新年伊始是制订塑身计划的好时候,努力做一个身材匀称、健康快乐的人。
最新回复
(
0
)