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
专升本
When aluminum was first produced about a hundred and fifty years ago, it was so difficult to separate from the ores(矿石) in which
When aluminum was first produced about a hundred and fifty years ago, it was so difficult to separate from the ores(矿石) in which
admin
2007-12-30
90
问题
When aluminum was first produced about a hundred and fifty years ago, it was so difficult to separate from the ores(矿石) in which it was found that its price was higher than that of gold. The price remained high until a new process was discovered for refining the metal with the aid of electricity approximately three quarters of a century later. The new method was so much cheaper that aluminum became practical for many purposes, one of which was making pots and pans.
Aluminum is lightweight, rustproof and easily shaped into different forms. By mixing it with other metals, scientist have been able to produce a variety of alloys, some of which have the strength of steel but weigh only one third as much.
Today, the uses of aluminum are innumerable. Perhaps its most important use is in transportation. Aluminum is found in the engines of automobiles, in the hulls of boats. It is also used in many parts of airplanes. In fact, the huge "airbus" planes would probably never have been produced if aluminum did not exist. By making vehicles lighter in weight aluminum has greatly reduced the amount of fuel needed to move them. Aluminum is also being used extensively in the building industry in some countries.
Since aluminum is such a versatile(多用的) metal, it is fortunate that bauxite(铝土矿) , which is one of its chief sources, is also one of the earth’s most plentiful substances. As the source of aluminum is almost inexhaustible, we can expect that more and more uses will be found for this versatile metal.
Aluminum is found on earth mostly in the form of______.
选项
A、pure metal
B、bauxite
C、gold
D、liquid
答案
B
解析
最后一段第一句…it is fortunate that bauxite(铝土矿),which is one of its chief sources,is also one of the earth’s most plentiful substances.作为铝的主要来源,铝土矿是地球上最丰富的物质之一,可知铝的形式主要是表现为“铝土矿”,故选B。
转载请注明原文地址:https://kaotiyun.com/show/ChLC777K
本试题收录于:
英语题库普高专升本分类
0
英语
普高专升本
相关试题推荐
设函数,其中δ(x)具有二阶导数,且δ(0)=1,δ’(0)=0,求f’(t).
Acontractisanagreementbetweentwoormorepeople【71】onepersonagreestodosomethingbyaspecifieddateinreturnfors
Airisa______(mix),whosecomponentsareofgreatuseinthechemicalindustry.
"Igetbywithalittlehelpfrommyfriends"isapopularlyric(抒情诗)withage-oldwisdombehindit.【B1】______peopleneedpeop
Thedayshegotmarriedisadayshewillalways______thoughherchildrenhavegrownupandalsogotmarried.
Wegotupearlythismorningand【61】alongwalkafterbreakfast.Wewalkedthroughthebusiness【62】ofthecity.Thecity【63
Iwas______thechanceofgoingtouniversitywhenmyparents’businesscollapsedandtheylosteverythingtheyowned.
ADespiteofhispoorhealthheworkedBuntilheCfinishedalltheDproceduresoftheexperiment.
Inthetraditionalmarriage,themanworkedatajobtoearnmoneyforthefamily.Mostmenworkedinanoffice,afactoryorso
—DoesJanestillpursueherdreamofbecomingamoviestar?—I’mafraidnot.Sheissaid______thestagealreadyasshegotm
随机试题
设随机变量X的分布函数为F(X),已知F(2)=0.5,F(一3)=0.1,则P{一3<X≤2}=__________.
组织文化的特征主要有()
患者,男性,46岁,有乙肝病史20年,近日因纳差、面黄至医院,查肝功能:ALT:67U/L,AST:84U/L,腹部彩超示肝脏弥漫性增大,大量腹水,诊断为乙型肝炎肝硬化,下列哪项检查结果错误
患儿,男,10月,发热、咳嗽、气喘4—5天,近2天腹泻大便3~4次/日,呈黄稀便,偶有呕吐,体检两肺可闻喘鸣音及湿性啰音,心音有力,律齐,心率136次/分,腹软,肝肋下2cm,质软,脾不大。患儿在治疗中突然喘憋加重,烦躁不安、发绀,体温38℃,呼吸70
1岁小儿未接种过卡介苗,PPD阳性表示
任务型教学途径中“任务”的特点“有差距”是指任务应与学生现有的知识能力有一定的差距,这些差距可以是知识差距、能力差距、技能差距、信息差距和——差距等。
我国社会主义改革是一场新的革命,其性质是()
形而上学唯物主义物质观的缺陷在于()
曲线的渐近线有().
TheInteractionofBodyandMindTheconceptofpsychosomaticillnessPsycho,referstomind,andsoma,tobody.Psychosom
最新回复
(
0
)