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
The railroad industry could not have grown as large as it did without steel. The first rails were made of iron. But iron rails w
The railroad industry could not have grown as large as it did without steel. The first rails were made of iron. But iron rails w
admin
2013-06-03
51
问题
The railroad industry could not have grown as large as it did without steel. The first rails were made of iron. But iron rails were not strong enough to support heavy trains running at high speeds. Railroad executives wanted to replace them with steel rails because steel was ten or fifteen times stronger and lasted twenty times longer. Before the 1870’s, however, steel was too expensive to be widely used. It was made by a slow and expensive process of heating, stirring, and reheating iron ore.
Then the inventor Henry Bessemer discovered that directing a blast of air at melted iron in a furnace would burn out the impurities that made the iron brittle (易碎的). As the air shot through the furnace, the bubbling metal would erupt in showers of sparks. When the fire cooled, the metal had been changed, or converted, to steel. The Bessemer Converter made possible the mass production of steel. Now three to five tons of iron could be changed into steel in a mater of minutes.
Just when the demand for more and more steel developed, prospectors, discovered huge new deposits of iron ore in the Mesabi Range, a 120-mile-long region in Minnesota near Lake Superior. The Mesabi deposits were so near the surface that they could be mined with steam shovels.
Barges and steamers carded the iron ore through Lake Superior to depots (车站) on the southern shores of Lake Michigan and Lake Erie. With dizzying speed, Gary, Indiana, and Toledo, Youngstown, and Cleveland, Ohio, became major steel-manufacturing centers. Pittsburgh was the greatest steel city of all.
Steel was the basic building material of the industrial age. Production skyrocketed from seventy-seven thousand tons in 1870 to over eleven million tons in 1900.
According to the passage, the railroad industry preferred steel to iron because steel was ______.
选项
A、cheaper and more plentiful
B、lighter, and easier to mold
C、cleaner, and easier to mine
D、stronger and more durable
答案
D
解析
第一段第3句:铁路部门希望用钢轨来代替铁轨,因为钢比铁坚固10—15倍,使用寿命是铁的20倍
转载请注明原文地址:https://kaotiyun.com/show/Hvg7777K
0
大学英语四级
相关试题推荐
A、She’sspendingtimegoingoverheraccounts.B、She’sbeenhomeforonlyafewdays.C、She’sexcitingaboutgoinghome.D、She’s
Itisoftenthroughgooddinnersthatonemakesfriends.InJapan,thereare【B1】______"DiningGroups"or"WineGroups",formedb
A、Itisfoundthatpeoplewhoworkatmentaljobsexperiencefewerheartattacksthanotherpeople.B、Itisfoundthatpeoplewh
Privatedoesnotmean【B1】______.Butitdoesmean【B2】______.PublicschoolsintheUSarepaidforbymoneyfromeveryone;pri
A、Bydoingbusiness.B、Bybuyingandsellingland.C、Bycheating.D、Bymakingwhiskey.AHowdidJohnsonbecomerichaccordingto
Oneoftheproblemsinourdailylivesisthatmanyofusrushthroughtheday,withnotimeforanything...andwhenwehavetim
Ifwomenaremercilessly(无情地)exploitedyearafteryear,theyhaveonlythemselvestoblame.Becausetheytrembleatthethough
AnAmericanweddingbeginswithengagement.Traditionally,ayoungmanasksthefatherofhis【S1】______forpermissiontomarry
Mostpeopleareawarethatoutdoorairpollutioncandamagetheirhealth,butmanydonotknowthatindoorairpollutioncanals
Hehasmanygood______requiredofanidealemployee--diligence,modesty,andsimplicity.
随机试题
农田生态系统经常采用______来加强对农副产品的转化和利用。
A、加强营养、增加体重、消除紧张B、扩张官腔,宫内放置节育器,同时给予雌、孕激素序贯治疗C、雌、孕激素合并应用D、克罗米芬促排卵E、口服溴隐亭治疗闭经泌乳综合征的治疗应选用
A.煅石膏B.煅牡蛎C.锻炉甘石D.煅石决明E.血余炭用扣锅煅法炮制的饮片是()。
某企业因管理不善导致库存外购农产品毁损30%,毁损的农产品总成本105万元,其中含运费成本5万元,则该企业应转出进项税额的下列计算中,正确的是()。
请认真阅读下列材料,并按要求作答。依据拟定的教学目标,设计导入环节并说明理由。
下列行为中,行政机关的做法构成滥用职权的是:
在新的历史时期,公安机关坚持全心全意为人民服务的宗旨,就要做到()。
下列关于北洋政府司法制度的说法,错误的是()。
WhatIsAnthrax(炭疽)?There’sbeenalotoftalkaboutanthraxonthenewslately.Somepeopleareworriedthatanthraxmayb
TheexpeditionhasleftfortheAndesandthereisno______whenitwillreturn.
最新回复
(
0
)