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
A new kind of radar has been developed for space-age travelers. A working laboratory model of a new system of radar that makes u
A new kind of radar has been developed for space-age travelers. A working laboratory model of a new system of radar that makes u
admin
2015-12-31
25
问题
A new kind of radar has been developed for space-age travelers. A working laboratory model of a new system of radar that makes use of a beam of light is said to be ten thousand times more accurate than the best comparable system of radar that uses microwaves.
The model has shown that this radar system (known as laser-doppler radar) can measure with absolute precision speeds varying from spaceship orbital injection velocities (速度) of five miles per second down to virtual stops—speeds of less than one ten thousandth of an inch per second. According to the scientists who are developing this system, such fine measures of velocity are of prime importance in space missions. In a rendezvous (会合, 会合点) between two spaceships, or in a landing approach by a vehicle onto an orbiting space station, a bump could rip open a ship’s skin, or a nudge (轻触) could knock the station out of its orbit.
The light-beam radar, which operates at a frequency of trillions of cycles per second, could easily detect and measure the movement of a vehicle edging up to a satellite space station even at a small fraction of an inch per second. A control system using so precise a signal as this would allow a huge vehicle to dock at a space station as lightly as a feather.
This laser-doppler radar will be especially valuable in space because________.
选项
A、the speeds of space vehicles will vary greatly
B、accurate measurements are essential in space
C、inaccuracies in measurement could cause accidents in space
D、all of the above
答案
D
解析
文中第二段第二句、第三句说:“据正在开发这个系统的科学家说,这样精确的速度测量对于太空飞行来说是头等重要的事情。这种精确的速度测量的重要性在于,当处在两艘宇宙飞船的会合点上,或当一个飞行器在一个轨道太空站进行着陆时,一次轻微碰触就有可能把飞船的外壳撕开一个口子或把太空站撞出其运行轨道。”由此我们可以得出选项B和C都符合题意;又根据文中第二段第一句可知选项A符合题意。而选项D说A、B、C三个选项都对,故本题正确答案为D。
转载请注明原文地址:https://jikaoti.com/ti/pFIYFFFM
0
在职攻硕英语联考
相关试题推荐
Accordingtoapoll,around70percentofAmericankidsstopplayingorganizedsportsbytheageof13because"it’sjustnotfu
Womenarehappytowanderaimlesslythroughaseaofclothingandaccessorycollectionsorlingerthroughtheshoedepartment.T
Teachingisnotall【C1】______thelatesttechnology.【C2】______it’seasytobecomecrazyaboutmoderntrends,wemustrecognizeth
______inasimplestyle,thebookclearlydescribestheauthor’schildhoodexperiencesinasmalltown.
Accordingtoaconcerned1997articleintheBostonGlobe,theUnitedStatesspentlessthanonepercentofitstransportationb
Hewasayoungmanofbarelyeighteenyears,evidentlycountry,andnow,asitseemed,onhisfirstvisittotown.
CustomsofficersataLondonairportyesterdayfound$500000worthofdrugswhichwerebeingsmuggledintoBritaininboxesma
Consumer______infoodproductshasbeenshakenbyseveralrecentscandals.
Inflationisaneconomicconditioninwhichpricesforconsumergoodsincrease,andthevalueofmoneyor【51】powerdecreases.Th
NancyJeschke’ssleepingdifficultiesbeganonvacationafewsummersago.Sheblamedthenoisymotelroom,buthersleepingdid
随机试题
女性,53岁,阴道不规则流血,超声显像见子宫浆膜下、肌壁和黏膜有多个大小不等结节,最可能诊断是()
A、治热以寒B、治寒以热C、阳病治阴D、阴病治阳E、阴中求阳阴虚发热证的治则是()
有关资金的时间价值推论不正确的一项为()。
住房公积金财务管理的主要任务:编制住房公积金和管理中心管理费用年度预决算,建立职工住房公积金明细账,记载职工个人住房公积金的缴存、提取等情况;建立健全内部财务制度,做好财务管理工作;降低运作风险,保证住房公积金保值增值,确保住房公积金所有者的合法权益不受侵
由一个力和一个力偶组成的平面力系()。
自理报关单位没有进出口经营权,但有报关权。()
2017年联合国迎来的新任秘书长是()。
“就业至上”是针对“就业难”提出来的。面对国际金融危机,今年高校毕业生就业遇到了前所未有的困难,各高校都把解决就业难问题作为“一把手工程”来抓,这本来无可厚非。但重视就业,为了走出困境,就把“就业至上”上升到办学理念的高度,有欠妥当。这段文字的主要
[2014年第42题]这两个《通知》或者属于规章或者属于规范性文件,任何人均无权依据这两个《通知》将本来属于当事人选择公证的事项规定为强制公证的事项。根据以上信息,可以得出以下哪项?
What’stheaverageincreaseperyearofforeignstudentpopulationintheperiodbetween1985and1990intermsofpercentage?
最新回复
(
0
)