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
A scorching sun, an endless sea of sand and a waterless, forbiddingly lonely land—that is the image most people have of deserts.
A scorching sun, an endless sea of sand and a waterless, forbiddingly lonely land—that is the image most people have of deserts.
admin
2010-02-19
55
问题
A scorching sun, an endless sea of sand and a waterless, forbiddingly lonely land—that is the image most people have of deserts. But how true is this picture? Deserts are drylands where rainfall is low. This is not to say rain never falls in deserts: it may fall once or twice a year in a fierce torrent that fades almost as soon as it has begun, or which evaporates in the hot air long before it has got anywhere near the earth. It may fall in a sudden sweeping flood that carries everything in its path. Rains may only come once in five or six years or not fall for a decade or more. The Mojave desert in the United States remained dry for twenty-five years.
Without water no living thing can survive, and one feature of the true desert landscape is the absence of vegetation. With little rain and hardly any vegetation the land suffers under the sun. There are virtually no clouds or trees to protect the earth’s surface and it can be burning hot. Under the sun, soils break up and crack. Wind and torrential rain sweep away and erode the surface further. Eight million square kilometers of the world’s land surface is desert. Throughout history deserts have been expanding and retreating again. Cave paintings show that parts of the Sahara Desert were green and fertile about 10,000 years ago, and even animals like elephants and giraffes roamed the land. Fossil and dunes found in fertile and damp parts of the world show that these areas were once deserts. But now the creation of new desert areas is happening on a colossal scale. Twenty million square kilometers, an area twice the size of Canada, is at a high to very high risk of becoming desert. With a further 1.25 million square kilometers under moderate risk, an area covering 30% of the earth’s land surface is desert, becoming desert, or in danger of becoming desert. The rate of growth of deserts is alarming. The world’s drylands which are under threat include some of the most important stock-rearing and wheat-growing areas and are the homes of 600--700 million people. These regions are becoming deserts at the rate of more than 58, 000 square kilometers a year or 44 hectares a minute. In North Africa at least 100,000 hectares of cropland am lost each year. At this rate there is a high risk that we will be confined to living on only 50% of this planet’s land surface within one more century unless we am able to do something about it.
How much of the world’s land surface is at risk of becoming desert?
选项
A、Less than ten million square kilometers.
B、Twenty million square kilometers.
C、Mom than twenty million square kilometers.
D、30% of the world’s land surface.
答案
C
解析
文章第二段中间有一句话“Twenty million square kilometers,an area twice the size of Canada,is at a high to very high risk of becoming desert.With a further 1.25 million square kilometers under moderate risk.”,这句话是说,2000万平方公里的土地面临着成为沙漠的高危险,而125万平方公里的土地有中度危险,加起来就是答案C——超过2000万平方公里的土地面临着成为沙漠的危险。
转载请注明原文地址:https://jikaoti.com/ti/oAkYFFFM
0
考博英语
相关试题推荐
AlotofmanagersareanxiousaboutWebservicesbecauseWithWebservices,theshipmentvolumeofBerkinsisexpectedtoincre
•Lookatthenotesbelow.•Someinformationismissing.•Youwillhearamangivingsomeinformationaboutaconference.•Forea
Ifthewomancomes,howmanypeoplearegoingontheboat?Howmuchdoesonepillowcost?
•Lookatthenotesbelow.•Someinformationismissing.•Youwillhearaconversationaboutmakingtravelarrangements.•For
•Lookatthenotesbelow.•Someinformationismissing.•Youwillhearaconversationaboutmakingtravelarrangements.•For
JustineisparticularlypleasedaboutthecompanyWhatproblemaretheyexperiencingwithJohnson’s?
Thesmallerversionspends______.
Lookatthenotesbelow.Someinformationismissing.YouwillhearareportonE-money.Foreachquestion(16-22),fillinthem
MemorandumToRosemaryWimpoleFromDrKittle,ResearchandDevelopmentDate3February1998Re
Nell’sfathersaidtohimthathewas______dogtolearnnewtricks.
随机试题
关于W-P小体的结构和功能是()
某一空调工程需冷量为2000kW,选用()制冷机运行能耗最低。
甲是某期货公司的首席风险官,在任职期间,由于一些违法行为被中国证监会认定为不适当人选,根据规定甲自被认定为不适当人选之日起()内,任何期货公司不得任用甲担任董事、监事和高级管理人员。
甲上市公司发生的下列事项中,可以按照公司章程的规定,由董事会决议的是()。
某城乡结合部社区有一些行为偏差青少年,他们有的存在不良行为,有的甚至受到过司法处置。为了帮助他们健康成长,社会工作者小王拟以社会连接理论为依据,为他们提供系列专业服务。小王应该为这些青少年提供的服务是()。
把自己的教学实践作为一个认识对象放在历史过程中进行思考和梳理,同时不断地获取学生的反馈意见,并把它作为另一个认识对象进行分析,最后把两个具体的认识对象进行整合思考。这种反思属于()。
2016年,某省完成邮政通信业务总量6886.15亿元,同比增长56.6%,增幅比上年提高27.4个百分点。其中,完成邮政业务总量1879.99亿元,增长53.0%,增幅提高11.0个百分点;完成通信业务总量5006.16亿元,增长58.0%,增幅提高3
有一批正方形的砖,排成一个大的正方形,余下47块;如果将它改排成每边长比原来多一块砖的正方形,就要差50块。问这批砖原有多少块?
金本位制
I’vealwaysbeenanoptimistandIsupposethatisrootedinmybeliefthatthepowerofcreativityandintelligencecanmaketh
最新回复
(
0
)