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
2015-12-01
61
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/ZOLO777K
0
考博英语
相关试题推荐
RichardSatava,programmanagerforadvancedmedicaltechnologies,hasbeenadrivingforcebringingvirtualrealitytomedicine
RichardSatava,programmanagerforadvancedmedicaltechnologies,hasbeenadrivingforcebringingvirtualrealitytomedicine
Mostofustelloneortwoliesaday,accordingtoscientistswhostudythesethings.Andwerarelygetcaught,becausethelie
Mostofustelloneortwoliesaday,accordingtoscientistswhostudythesethings.Andwerarelygetcaught,becausethelie
Mostofustellonetwoliesaday,accordingtoscientistswhostudythesethings.Andwerarelygetcaught,becausetheliesw
ThegeologyoftheEarth’ssurfaceisdominatedbytheparticularpropertiesofwater.PresentonEarthinsolid,liquid,andgase
Summerholidaysspentonthehotghettostreetsare______thetimemiddle-classstudentsdevotetocamps,exoticvacationsandhi
(浙江大学2010年试题)ThecharacterofEuropeaneducationdemandsthatthestudentdevelop【1】andsocialindividuality.TheAmerican
(浙江大学2010年试题)ThecharacterofEuropeaneducationdemandsthatthestudentdevelop【1】andsocialindividuality.TheAmerican
随机试题
Shouldyoungcriminalsbetreatedinthesamewayasadults?Thisissuehasbeenintenselydiscussedforyears.Thefollowingar
患者,女性,58岁,诊断为风湿性心脏病二尖瓣狭窄10年,目前患者休息时仍感心悸、气促,双肺可闻及湿啰音。据此可判断其心功能分级属于
王某,女,38岁。疲劳过度,出现眩晕昏仆,面色苍白,呼吸微弱,汗出肢冷,舌质淡,脉沉微。宜诊断为
不属于中药品种保护目的的是
根据《刑法》规定,对于()不适用缓刑。
A车以110km/h的速度由甲地驶往乙地,同时B,C两车分别以90km/h、70km/h的速度自乙地驶向甲地,途中A与B相遇1小时后才与C车相遇,则甲乙两地的距离是()km。
环保汽车
在考生文件夹下有一个工程文件sjt5.vbp,其窗体中有一个实心圆。程序运行时,当用鼠标左键单击窗体任何位置时,实心圆则向单击位置直线移动;若用鼠标右键单击窗体,则实心圆停止移动。窗体文件中已经给出了全部控件,但程序不完整。要求:请去掉程序中的注释符,把
软件生命周期是指()。
GunRightsintheUSImmediatelyaftertheshootingatVirginiaTechUniversity,Americansgatheredtomournthedead.Thepresi
最新回复
(
0
)