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
34
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://jikaoti.com/ti/492FFFFM
0
大学英语四级
相关试题推荐
Largeancientanimalsaresupposed__________(曾经生活在这个地区).
____________(据估计)overonehundredthousandpeoplehaveleftthepeninsula.
AcademyAwardsEveryFebruaryOscarFeverhitstheentertainmentcommunityandfilmfansaroundtheworld.Hundredsofmilli
Rumoristhemost【C1】______wayofspreadingstories---bypassingthemonfrommouth【C2】______month.Butcivilizedcountriesinn
Rumoristhemost【C1】______wayofspreadingstories---bypassingthemonfrommouth【C2】______month.Butcivilizedcountriesinn
AIDSAcquiredImmunodeficiencySyndrome(AIDS),isakindofhumanviraldisease(病毒病)thatdamagestheimmunesystem,weake
ThebirthoftheSpaceTransportationSystem(STS)andtheneweraofspaceactivitiesitwillbringarecontributingtoarecen
ThebirthoftheSpaceTransportationSystem(STS)andtheneweraofspaceactivitiesitwillbringarecontributingtoarecen
Ifwomenaremercilessly(无情地)exploitedyearafteryear,theyhaveonlythemselvestoblame.Becausetheytrembleatthethough
A、Sheishavingaheartattack.B、Shewashurtinanaccident.C、Sheishavingababy.D、Shehaslostconsciousness.C同义再现。labo
随机试题
磨牙反锁牙合的描述为
下列中毒性细菌性痢疾的治疗措施,错误的是()
()等国家规定的特种作业人员,必须按照国家规定经过专门的安全作业培训,并取得特种作业操作资格证书后,方可上岗作业。
下列( )是产权登记的组成要素。
法定盈余公积金与任意盈余公积金的主要区别在于。前者是法律规定必须提取的,后者是根据股东大会或者股东会的决议提取。()
万达公司为增值税一般纳税企业,适用的增值税税率为17%。2002年8月30日,万达公司和明洁公司签订协议,向明洁公司销售一批商品,增值税专用发票上注明销售价格为200万元,增值税额为34万元。协议规定,万达公司应在11月30日将所售商品购回,回购价为21
墨守成规对于()相当于()对于谦虚
一种三个月期(90天)的美国国库券面值为1000美元,发行时的售价为990美元,试计算其贴现收益率和债券等价收益率(计算结果保留小数点后四位数字)。
LivinginthecentralAustraliandeserthasitsproblems,______obtainingwaterisnottheleast.
A、$800.B、$850.C、$1000.D、$1050.D
最新回复
(
0
)