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、A battery-operated system on the train will control and bring the cars to a smooth stop. B、The magnetic attraction will hook t
A、A battery-operated system on the train will control and bring the cars to a smooth stop. B、The magnetic attraction will hook t
admin
2013-06-03
86
问题
What does maglev look like? Japanese engineers designed a vehicle that runs in a cradle-like track or guideway. Magnetic attraction and repulsion pull and push maglev forward. To stop the trains, the magnetic force is reversed, much like airplanes are stopped by reversing the force of the engines. Both types of maglev are quiet, fast, and save. Since maglev rides on air, there is no friction between wheels and rails to make noise or to slow it down. If the external power fails, there is a battery-operated system on the train itself that takes over and brings the cars to a smooth stop.
Maglev could be the answer to our problems. It could become the typical short and middle-distance mass transportation system of the twenty-first century. If it does, we will enjoy many benefits. We will ride in save, fast, quiet trains between cities up to about 500 miles apart in less time than it takes to fly if you include the time for ground transportation. We will conserve precious land because maglev can be built where railroads run, down the middle of existing super-highways or elevated above existing streets and roads. And we will probably save money, too. According to a German estimate, a mile of two-way track will cost about nine million dollars whereas a mile of interstate highway costs about 25 million dollars in the United States.
选项
A、A battery-operated system on the train will control and bring the cars to a smooth stop.
B、The magnetic attraction will hook the cars firmly.
C、The cars equipped with a device will run in a special guide way.
D、The internal power will keep the cars steady.
答案
A
解析
转载请注明原文地址:https://kaotiyun.com/show/qvg7777K
0
大学英语四级
相关试题推荐
Rumoristhemost【C1】______wayofspreadingstories---bypassingthemonfrommouth【C2】______month.Butcivilizedcountriesinn
Rumoristhemost【C1】______wayofspreadingstories---bypassingthemonfrommouth【C2】______month.Butcivilizedcountriesinn
A、Childrenarealwayshappytomovetoanewcity.B、Movingbringstheopportunitiesaswellassomeproblems.C、Husbandandwif
A、Howtosolveproblems.B、Someonewhomtheycanrelyon.C、Someonewhowilllistentothem.D、Whatarealfriendshouldbe.D根据
Mostpeopleareawarethatoutdoorairpollutioncandamagetheirhealth,butmanydonotknowthatindoorairpollutioncanals
A、Therelationshipofpurchasestotimespentinshopping.B、Thelengthoftimerequiredfordrugstoreshopping,C、Theincreases
Itiseasiertonegotiateinitialsalaryrequirementbecauseonceyouareinside,theorganizationalconstraints(约束)influence
A、Runintown.B、Joggingmorecarefully.C、Buyshoesfromacatalog.D、Findaneasierplacetoexercise.C[听力原文]M:Ican’tfind
随机试题
女性患者,23岁。间歇性心悸,气促3年,劳累时加重。1周前受凉后出现发热、咽痛、咳嗽,4天前出现心悸和气促加剧,双下肢水肿。查:T37℃,R34次/分,P108次/分,律不整,BP80/50mmHg。半坐位,四肢指(趾)端及唇轻度发绀,扁桃体Ⅱ度
运用成本法对房地产价格评估,其使用范围主要是()。
企业自动化物流系统的目标和作用是增强快速反应能力,增强创新能力和竞争能力、提高效益和______。
干燥的冷空气和富含水蒸气的暖空气相遇,发生大规模碰撞时形成的极端天气现象是:
2015年,全国文化及相关产业增加值27235亿元,比上年增长11%(未扣除价格因素),在2014年增长12.2%的基础上继续保持两位数增长,呈快速增长态势。2015年文化及相关产业增加值占GDP的比重为3.97%,比上年提高0.16个百分点。2
Readingtooneselfisamodernactivitywhichwasalmostunknowntothescholarsoftheclassicaland【C1】______worlds,whiledur
当拖动滚动条中的滚动框时,将触发的滚动条的事件是()
Ifsustainablecompetitiveadvantagedependsonworkforce,skills,Americanfirmshaveaproblem.Human-resourcemanagementis
InEnglish,thewordaboutcolourcanreflectdifferentemotions.Blueandgreymeanbadmoodandredmeansvitality.Youmightth
Thetwopartiesreachedanagreementafternegotiatingindetails.
最新回复
(
0
)