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
Volcanoes are the ultimate earth-moving machinery. Eruptions have rifted continents, raised mountain chains, constructed islands
Volcanoes are the ultimate earth-moving machinery. Eruptions have rifted continents, raised mountain chains, constructed islands
admin
2015-01-31
36
问题
Volcanoes are the ultimate earth-moving machinery. Eruptions have rifted continents, raised mountain chains, constructed islands and shaped the topography of the earth. The entire ocean floor has a basement of volcanic basalt.
Volcanoes have not only made the continents, they are also thought to have made the world’ s first stable atmosphere and provided all the water for the oceans, rivers and ice-caps. There are now about 600 active volcanoes. Every year they add two or three cubic kilometers of rock to the continents. Imagine a similar number of volcanoes smoking away for me last 3,500 million years. That is enough rock to explain the continental crust.
What comes out of volcanic craters is mostly gas. More than 90% of this gas is water vapor from the deep earth: enough to explain, over 3,500 million years, the water in the oceans. The rest of the gas is nitrogen, carbon dioxide, sulphur dioxide, methane, ammonia and hydrogen. The quantity of these gases, again multiplied over 3,500 million years, is enough to explain the mass of the world’s atmosphere. We are alive because volcanoes provided the soil, air and water we need.
Geologists consider the earth as having a molten core, surrounded by a semi-molten mantle and a brittle, outer skin. It helps to think of a soft-boiled egg with a runny yolk, a firm but squishy white and a hard shell. If the shell is even slightly cracked during boiling, the white material bubbles out and sets like a tiny mountain chain over the crack—like an archipelago of volcanic islands such as the Hawaiian Islands. But the earth is so much bigger and the mantle below is so much hotter.
Even though the mantle rocks are kept solid by overlying pressure, they can still slowly ’flow’ like thick treacle. The flow, thought to be in the form of convection currents, is powerful enough to fracture the ’eggshell’ of the crust into plates, and keep them bumping and grinding against each other, or even overlapping, at the rate of a few centimeters a year. These fracture zones, where the collisions occur, are where earthquakes happen. And, very often, volcanoes.
Where do volcanoes and earthquakes often occur?
选项
A、Those zones which are easily have a collision.
B、Those zones which are located alongside shores.
C、Far away from oceans.
D、The molten core.
答案
A
解析
细节题。题干问,火山与地震多发生在什么地方?根据关键词“earthquakes”定位于最后一段, “These fracture zones.where the collisions occur.are whereearthquakes happen.And,very often,volcanoes.”破碎的地方,也就是碰撞常常发生之处,地震和火山出现比较频繁。
转载请注明原文地址:https://kaotiyun.com/show/SLh7777K
0
大学英语六级
相关试题推荐
A、ThelecturefornextMondayiscancelled.B、Thelecturewasn’tassuccessfulasexpected.C、Thewomanhasnochanceforthele
A、Paintingapicture.B、Hostingaprogram.C、Designingastudio.D、Takingaphotograph.B根据女士所说的“今天我们请布朗教授带着他的新书《时尚映像》来到我们演播厅”,可
A、Shewantstoquitherjobinthechemistrylab.B、Shewantstogetpracticalexperience.C、Sheisinterestedinpsychologymaj
A、Shestartedtodoexperimentwithmakingprints.B、SheparticipatedintherebelliousImpressionists.C、Shehadherpaintings
Largecompaniesneedawaytoreachthesavingsofthepublicatlarge.Thesameproblem,onasmaller【B1】______,facespractica
A、Midnineteenthcentury.B、Latenineteenthcentury.C、Mideighteenthcentury.D、Lateeighteenthcentury.A短文谈到,美国有很多中国餐馆,超市里也卖中
年画(NewYearPainting)是中国画的一种,始于古代的门神画(doorgodpainting),在清朝光绪年间正式被称为年画。北宋年间,每逢过年过节家家户户贴年画已成为一种风尚。木板年画历史悠久,堪称中国民间艺术宝库中的一颗明珠。木版年画
A、Hermother’sinstruction.B、OneofMary’spaintings.C、Astrangewayofpainting.D、ArtistsintheMiddleAges.B短文最后提到自己最后一次去
A、Tohelppeopleunderstandhorsesbetter.B、Tohelppeopleenjoyafamilyatmosphere.C、Tohelppeoplehavefunaboveotherthi
A、ShehasdecidednottogotoAustralia.B、Shehasn’tmadeadecisionwhattodo.C、HerfriendjustreturnedfromAustralia.D、
随机试题
彩色显示器的彩色是由三基色合成而得到的。某显示器的三基色R、G、B分别用5位二进制数表示,则它可以表示___________种不同的颜色。
关于胆管癌的描述,下列哪项是错误的
门诊患者的病理资料保存年限应是
异径管的安装工程量计算是按()计算的。
下列说法错误的是()。
下列关于燃料电池的表述正确的是()。
A、 B、 C、 D、 D这是一个无理式数列,因为可知2,4,6,…,10为等差数列;1,2,4,…,16为等比数列,则空缺项为=0,选D。
根据历史上的真人真事进行文艺创作时,为了使人物表现得更为____________,可以对人物进行符合本身和时代背景的“适当”创作,但是大的历史事实、人物命运、主要矛盾、重要事件都必须符合历史,不能对历史人物的“人生层面”进行____________和歪曲。
电视纪录片也可以采用()手法。
Thefirehascausedgreatlosses,butthefactorytriedtominimizetheconsequencesbysayingthat______(损失没有报道的那么严重).
最新回复
(
0
)