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
Scientists say there has been a severe decrease in the amount of water in Lake Chad in northern Africa in the last thirty years.
Scientists say there has been a severe decrease in the amount of water in Lake Chad in northern Africa in the last thirty years.
admin
2011-01-05
63
问题
Scientists say there has been a severe decrease in the amount of water in Lake Chad in northern Africa in the last thirty years. They reported that nature and humans share equal blame for this loss.
In 1963, the fresh-water lake covered 25,000 square kilometers. Now the lake is only about five percent of that size. It measures only about 1,300 square kilometers in the dry season.
Four nations surround Lake Chad. People in Niger, Nigeria, Chad, and Cameroon use it for water, fish and plant life.
Michael Coe and Jonathan Foley, water experts at the University of Wisconsin in Madison, reported on Lake Chad in a science journal. They say the area has suffered from a lack of heavy rain for more than thirty years. This has forced people to build systems to carry water to dry land. These irrigation systems further decrease the amount of lake water.
Mr. Coe says Lake Chad will be only a small body of water in the future. He says people still can get water from the lake to drink and for crops. But he says the lake will no longer provide a healthy environment for fish and plant life.
The researchers used a computer to study what caused the water loss. Their computer study estimated the climate and amount of water in the area. The estimate started with written records from the early 1960s. Then the researchers compared the estimates with the area’s recorded climate and water supply for the same period.
The computer study showed results similar to the recorded ones for the first twenty years. But there was a big change in the 1980s. At the time, the lake got smaller much faster than the computer research had estimated.
The researchers say that major irrigation systems were built in the 1980s. The systems took water from two rivers that flow into Lake Chad. The Chari and Logone rivers carry most of the water that enters the lake. Climate changes also were responsible for the reduction. The flow of the two rivers was reduced by almost seventy-five percent.
Scientists say the problem is expected to worsen in the coming years as the population and demand for water continued to increase.
The water that the Chari and Logone rivers carry is now ______ percent of the flow of the past.
选项
答案
twenty-five
解析
转载请注明原文地址:https://kaotiyun.com/show/8PVK777K
本试题收录于:
C类竞赛(非英语专业本科)题库大学生英语竞赛(NECCS)分类
0
C类竞赛(非英语专业本科)
大学生英语竞赛(NECCS)
相关试题推荐
DearSirs,(1)Yourshipmentoftwelvethousand"Smart"watcheswasreceivedbyourcompanythismorning.However,wewisht
(1)AppleInc.wantstotakebackcontrolofhowusersconsumemediaonitsdevices.(2)Thecompanypioneeredthemovetod
NewwordsentertheEnglishlanguageallthetime.Infact,Englishhasalwaysbeeninastateof【T1】________.Andinrecentyea
Goodafternoon,everybody.Thankyouverymuchforinvitingmeheretotalkaboutsafetyindormitoryand【T1】________.First,a
Goodafternoon,everybody.Thankyouverymuchforinvitingmeheretotalkaboutsafetyindormitoryand【T1】________.First,a
________threegirls,IhavealwaysbelievedthatMaryisthe________beautiful.
Theraysofthemorningsunbegintoshinethrough________windows,castingaglowofgoldoverthelandscape.
Aleading________intelligenceandoperationscompanyhasreleaseditsanalysisofworldwidereportedincidentsofpiracyandcr
Thejobseekerfilledintheapplicationform,butshedidn’tknowwhichofficeroom________.
Whatpoliticianscherishmostisthebenefitsoftheirparties.Theunderlinedpartmeans________.
随机试题
下列目标属于商品定价目标的有()。
下列药物属于流感病毒的神经氨酸酶抑制剂的是()。
高层建筑的消防控制室、消防水泵、消防电梯、防烟排烟风机等的供电,应在最末一级配电箱处设置()装置。
当供暖管道温度不大于100℃时,其与可燃物之间的设置要求是()。
《导游人员管理实施办法》规定,导游人员在导游活动中有()情形,将扣除4分。
阅读材料,根据要求完成任务。材料一《义务教育化学课程标准(2011年版)》关于“溶解度”的内容标准为“了解饱和溶液和溶解度的含义”。材料二桌版本教科书中有关溶解度的内容如下:二、溶解度通过上述实验,我们大致可
【2017江西】王某担任某县高二英语教师期间通过了硕士研究生人学考试,学校以王某服务期未满、学校英语教师不足为由不予批准王某在职学习。王某欲以剥夺其参加进修权利为由提出申诉,受理申诉的机构应当是()。
根据以下资料,回答106—110题。2009--2012年间一次能源生产量增速最快的一年是()。
ThewritercametoLondonfrom______.Englishmen______.
ManypeoplerushedtoCaliforniabecause______.Whichofthefollowingmaybethebesttitleofthepassage?
最新回复
(
0
)