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
考研
The long, wet summer here in the northeastern U. S. notwithstanding, there’s a world shortage of pure, fresh water. As demand fo
The long, wet summer here in the northeastern U. S. notwithstanding, there’s a world shortage of pure, fresh water. As demand fo
admin
2015-01-15
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.
Streams would purify themselves if not for______.
选项
A、human beings
B、nature
C、chlorination
D、mountains
答案
A
解析
从第3段可知,在没有干预的情况下,大自然有自己的方式净化水源。因此A项为正确答案。
转载请注明原文地址:https://kaotiyun.com/show/jchi777K
0
在职申硕(同等学力)英语
相关试题推荐
Musiccomesinmanyforms;mostcountrieshaveastyleoftheirown.【C1】______theturnofthecenturywhenjazz(爵士乐)wasborn,Am
Ourbodiesarewonderfullyskillfulatmaintainingbalance.Whenthetemperaturejumps,wesweattocooldown.Whenourbloodpr
Learningdisabilitiesareverycommon.Theyaffectperhaps10percentofallchildren.Fourtimesasmanyboysasgirlshavelea
Therecentfindingsarealsoapplicabletootherareasofdesignengineering.
Accordingtothepassage,thevolunteers______.TherearemoreolderpeoplewhowanttodoVSObecause______.Ⅰ.morepeoplet
Inasense,farmersbeganprimitivegeneticengineering(atthedawnof)agriculture,(which)theykeptseeds(from)theirbest
Technologyhas______thesharing,storageanddeliveryofinformation,thusmakingmoreinformationavailabletomorepeople.
(Unable)toseetheirbusinessasaseparateentity,manypeoplefailtomake(a)distinction(between)theircompanyand(them)
SostrangewerethecircumstancesofmystorythatIcanscarcelybelievemyselftohavebeenapartytothem.
Intheearly20thcentury,fewthingsweremoreappealingthanthepromiseofscientificknowledge.Inaworldstrugglingwithr
随机试题
InChina,over84percentofemployerschosetogiveyear-endbonuses(奖金)totheiremployeeswithclosetohalfthecompaniesp
安女士,产后7天,腹痛,发热39℃,恶露混浊有臭味,检查子宫复旧不佳,有压痛患者持续高热,下肢疼痛,且放射至右腹股沟,右下肢肿胀,还应考虑的诊断是()
A.尿糖测定B.血葡萄糖测定C.葡萄糖耐量试验D.糖化血红蛋白Al和糖化血浆白蛋白测定E.浆胰岛素C-肽测定
男性,48岁,市政铺路工,接触沥青25年,干咳,右上胸痛2个月,加重1周,抗炎无效。胸片:右上肺门增宽,右上叶体积缩小。考虑诊断是
血气分析时,标本采集处理中,错误的做法是
Ⅱ型超敏反应( )。
以下对土地所有权的理解中,错误的是()。
投标报价的基础和前提是()。
主承销商在定价之前,首先要确定恰当的市场时机,因为在不恰当的情况下发行,可能会长期性地损害发行者的市场声誉,从而限制了发行者未来的融资选择。( )
【11】【18】
最新回复
(
0
)