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
The long, wet summer here in the northeastern U.S. notwithstanding, there’s a world shortage of pure, fresh water. As demand for
admin
2017-08-15
28
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/XKFO777K
0
考博英语
相关试题推荐
Today,cigarettesmokingisawidespreadhabit.About43percentoftheadultmenand31percentoftheadultwomenintheUSsm
Painting,theexecutionofformsandshapesonasurfacebymeansofpigment,hasbeen【C1】______practicedbyhumansforsome20,
Asoneworkswithcolorinapracticalorexperimentalway,oneisimpressedbytwoapparentlyunrelatedfacts.Colorasseenis
Publicimagereferstohowacompanyisviewedbyitscustomers,suppliers,andstockholders,bythefinancialcommunity,bythe
Between5,000millionand4,000millionyearsagotheEarthwasformed.By3,000millionyearsagolifehadarisenandwehav
Between5,000millionand4,000millionyearsagotheEarthwasformed.By3,000millionyearsagolifehadarisenandwehav
ToliveintheUnitedStatestodayistogainanappreciationforDahrendorf’sassertionthatsocialchangeexistseverywhere.T
Makeupyourmindthatwhatevertheshort-termtemptationsmaybe,youwillnever______fromthehigheststandardsofhonor.
WhydosomanyAmericansdistrustwhattheyreadintheirnewspapers?TheAmericanSocietyofNewspaperEditorsistryingtoans
Irejectanyreligiousdoctrinethatdoesnot______toreasonandisinconflictwithmorality.
随机试题
Thepopulationofourcityisaboutthreetimesaslargeas________oftheirs.
A、末梢神经炎B、听力障碍C、视神经炎D、肝功能损害E、胃肠道不适链霉素的主要不良反应是()
法洛四联征不包括下列哪一种畸形
在会计电算化信息系统的开发与应用中,()是电算化系统的应用阶段。
某甲对A市B区公安分局管辖的一派出所作出的罚款30元的处罚决定不服。若某甲提出行政复议,他应向哪个机关申请?()
从所给的四个选项中,选择最合适的一个填入问号处,使之呈现一定的规律性。
公安机关的督察机构对人民警察的执法活动进行现场督察,这种形式的监督称为事中监督。()
TheXinhuabookstorechain,China’slargestofficialpublishingenterprise,hasbecomeasurprisingflashpointforinterestamo
指令系统是否精简的问题上,产生了两大类计算机系统,它们的英文缩写分别是CISC和_____。
Doctorsbelievethatsecond-handsmokemaycauselungcancerinpeoplewhodonotsmoke.Nonsmokersoftenbreatheinthesmokef
最新回复
(
0
)