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 long, wet summer here in the northeastern U.S.notwithstanding, there’s a world shortage of pure, fresh water.As demand for w
The long, wet summer here in the northeastern U.S.notwithstanding, there’s a world shortage of pure, fresh water.As demand for w
admin
2015-05-29
64
问题
The long, wet summer here in the northeastern U.S.notwithstanding, there’s a world shortage of pure, fresh water.As demand for water hits the limits of finite supply, potential conflicts are brewing between nations that share transboundary freshwater reserves.
Many people ask why we cannot simply take it from the sea, using our sophisticated technology of desalinization.But a good water supply must be hygienically safe and pleasant tasting and water containing salt would corrode machinery used in manufacturing in addition to producing chemical impurities.Since more than 95% of our water sits in the salty seas, man is left to face the reality that most water on the surface of the earth is not available for us.
One very feasible way of sustaining our supply of freshwater is to protect the ecology of our mountains.Mountains and water go together, a fact to which Secretary General Kofi Annan has drawn attention more than once.From 30% to 60% of downstream fresh water in humid areas and up to 95% in arid and semi-arid environments are supplied by mountains.Without interference nature has its own way of purifying water-even though chlorination and filtration are still necessary as a precaution.In a mountainous area, aeration, due to turbulent flow and waterfalls, causes an exchange of gases between the atmosphere and the water.Agriculture, industry, hydroelectric generators and homes that need water to drink and for domestic use depend on these resources and, thus, we must protect mountainous areas as a means of survival.
By saying that nature "has its own way of purifying water" (Line 5, Para.3) the author is referring to______.
选项
A、aeration
B、filtration
C、chlorination
D、absorption
答案
A
解析
本题中大自然净化水源的方式指的是后文提到的充气。因此A项为正确答案。
转载请注明原文地址:https://kaotiyun.com/show/RYLO777K
0
考博英语
相关试题推荐
TwosystemofweightsandmeasuresexistintheU.S.today:theU.S.CustomarySystemandtheInternationalSystemofUnits(I
Opinionpollsarenowbeginningtoshowanunwillinggeneralagreementthat,whoeveristo【21】andwhateverhappensfromnowon,
RichardSatava,programmanagerforadvancedmedicaltechnologies,hasbeenadrivingforcebringingvirtualrealitytomedicine
Itisoftendifficultto______betweenamereexaggerationandadeliberatelying.
Everylivingthinghasaninnerbiologicalclockthatcontrolsbehavior.Theclockworksallthetimeevenwhentherearenoout
Whowouldhavethoughtwewouldbecomeaplanetof"ologies"?There’sbiology,psychology,herpetology,etymology,andgeologyj
Itisapleasuretoseemenofacertainageworryingabouttheirweight.Listeningtothemisnotsuchapleasure.Becausethe
Theenergycontainedinrockwithintheearth’scrustrepresentsanearlyunlimitedenergysource,butuntilrecentlycommercial
Ingeneral,matterswhichlieentirelywithinstatebordersarethe______concernofstategovernments.
Tight-lippedeldersusedtosay,"It’snotwhatyouwantinthisworld,butwhatyouget."Psychologyteachesthatyoudogetwh
随机试题
什么是虚拟存储器?它有什么特点和作用?
患者要求引产,以下何种方式最安全引产后,采用何种避孕措施为宜
关于基础体温测定,下列哪项不恰当
不属于体外检测尿液HCG的方法是
行心脏DSA,显示二尖瓣瓣口的最佳投射位置是
《注册土木工程师(岩土)执业及管理工作暂行规定》规定,注册土木工程师(岩土)在执业过程中,应及时、独立地在规定的岩土工程技术文件上签章。以下哪项岩土工程技术文件不包括在内?()
按照《火灾统计管理规定》(公安部、劳动部,1997年)规定,这起事故按严重程度应定为()事故。该商厦存在的火灾隐患是()。
质量控制点的重点控制对象主要包括10个方面的内容,其中不属于特殊地基或特种结构方面内容的是()。
•Readthefollowingletter.•Choosethebestwordtofilleachgap.•Foreachquestion(19-33),markoneletter(A,B,CorD)o
A、Hisbossmightaskhimtostayuplate.B、Thewomanwillrecordtonight’sprogram.C、Hemayhavetopreparefortomorrow’sbus
最新回复
(
0
)