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
2015-01-09
88
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 dry lands 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 kilo-meters of the world’s land surface is desert. Throughout history deserts have been expanding and re-treating 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 fer-tile 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 dry lands 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 are 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 are 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、More than twenty million square kilometers.
D、30% of the world’s land surface.
答案
C
解析
根据文章第二段中间的一句话“Twenty million square kilometers,an area twice the size of Cana—da,is at a high to very high risk of becoming desert.With a further 1.25 million square kilometers un—der moderate risk.”分析这句话可知,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,因此C项为正确答案。
转载请注明原文地址:https://kaotiyun.com/show/42LO777K
0
考博英语
相关试题推荐
Peoplethinkingabouttheoriginoflanguageforthefirsttimeusuallyarriveattheconclusionthatitdevelopedgraduallyas
"Betweenyouandme,hesaidyouareagoodfornothing.""______"
Cultureisactivityofthought,andreceptivenesstobeautyandhumanefeeling.【1】ofinformationhavenothingtodowithit.Am
Thepolicelethimgo,becausetheydidn’tfindhimguilty______themurder.
Theworldisfacingthe______ofwatershortagescausedbypopulationgrowth,unevensuppliesofwater,pollution,andotherfact
Shesaidthatthetreatmentshehadreceivedinthehospitalhadcompletely______herofherdignity.
TheEnglishlanguagecontainsa(n)______ofwordswhicharecomparativeseldomusedinordinaryconversation.
71.Vacationswereoncetheprerogativeoftheprivilegedfew,evenaslateasthe19thcentury.Nowtheyareconsideredtherig
Wheneveryouseeanoldfilm,evenonemadeaslittleastenyearsago,youcannothelpbeingstruckbytheappearanceofthewo
随机试题
所反映的对象不是一个集合体的概念称为()。
患者,25岁,农民。面色苍白,疲乏无力1年。血常规检查RBC2.0×1012/L,Hb50g/L,喊7.6×109/L,中性粒细胞0.50,淋巴细胞0.26,嗜酸性粒细胞0.14,SF:10μg/L,血片中成熟红细胞中央淡染区扩大,拟诊为缺铁性贫血。根
某分部分项工程的清单编码为010302006004,则该分部分项工程的清单项目顺序编码为()。
某企业2002年末资产负债资料如下:流动资产1550万元.固定资产原价2420万元,其中:生产经营用1500万元,累计折旧860万元,其中:本年折旧120万元,资产总计3270万元,负债合计1880万元,长期负债1160万元,未发生待处理固定资产净损失
市场监管部的主要职责包括( )。
下列选项中,属于妻子一方的财产的是()。
关于急性短暂性精神障碍,正确的说法包括()。
实施综合实践活动的关键是倡导学生对课题的自主选择和主动实践。()
WhenyouwatchafootballgameonaSaturdayafternoon,youfeelsecureinyourknowledgeofwhatwillhappenwhenaplayerboot
Large,multinationalcorporationsmaybethecompanieswhoseupsanddownsseizeheadlines.Buttoafargreaterextentthanmo
最新回复
(
0
)