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
The Earth comprises three principal layers: the dense, iron-rich core, the mantle made of silicate (硅酸盐) that are semi-molten at
The Earth comprises three principal layers: the dense, iron-rich core, the mantle made of silicate (硅酸盐) that are semi-molten at
admin
2018-05-09
61
问题
The Earth comprises three principal layers: the dense, iron-rich core, the mantle made of silicate (硅酸盐) that are semi-molten at depth, and the thin, solid-surface crust. There are two kinds of crust, a lower and denser oceanic crust and an upper, lighter continental crust found over only about 40 percent of the Earth’s surface. The rocks of the crust are of very different ages. Some continental rocks are over 3,000 million years old, while those of the ocean floor are less than 200 million years old. The crusts and the top, solid part of the mantle, totaling about 70 to 100 kilometers in thickness, at present appear to consist of about 15 rigid plates, 7 of which are very large. These plates move over the semi-molten lower mantle to produce all of the major topographical (地形学的) features of the Earth. Active zones where intense deformation occurs are confined to the narrow, interconnecting boundaries of contact of the plates.
There are three main types of zones of contact: spreading contacts where plates move apart, converging contacts where plates move towards each other, and transform contacts where plates slide past each other. New oceanic crust is formed along one or more margins of each plate by material issuing from deeper layers of the Earth’s crust, for example, by volcanic eruptions (爆发) of lava (火山 熔岩) at mid-ocean ridges. If at such a spreading contact the two plates support continents, a rift (裂缝 ) is formed that will gradually widen and become flooded by the sea The Atlantic Ocean formed like this as the American and Afro-European plates moved in opposite directions. When two plates carrying continents collide, the continental blocks, too light to be drawn down, continue to float and therefore buckle (起褶皱) to form a mountain chain along the length of the margin of the plates.
Seriously-deformed zones appear_____.
选项
A、whenever the crusts move over mantle
B、when the plates move towards each other
C、in the narrow boundaries where two plates meet
D、to be the major topographical feature of the Earth
答案
C
解析
事实细节题。选项C是对第1段最后一句的同义改写。文章中没有提到选项A中the crusts move overmantle这种现象;选项B提到的现象在第2段第1句才讨论到,与题干无关;文中也没有提到严重变形的地区是地球的主要地形特征,因此选项D不正确。
转载请注明原文地址:https://www.kaotiyun.com/show/KI47777K
0
大学英语四级
相关试题推荐
Manyprivateinstitutionsofhighereducationaroundthecountryareindanger.Notallwillbesaved,andperhapsnotalldeser
HalloweenA)OnOctober31st,dozensofchildrendressedincostumesknockontheirneighbors’doorsandyell"TrickorTreat
HintsandTipstoSaveMoneyA)Spendless.Thisisnotoversimplifyingthebestwaytosavemoney!Itisessentialifyouar
Carsandotherroadvehiclesarethesinglemainsourceofharmfulnitrogenoxides.Roadtransportremainsthebiggestsourc
HintsandTipstoSaveMoneyA)Spendless.Thisisnotoversimplifyingthebestwaytosavemoney!Itisessentialifyoua
"Youneedanapartmentaloneevenifit’soveragarage",declaredHelenGurleyBrowninher1962bestsellerSexandtheSingle
"Youneedanapartmentaloneevenifit’soveragarage",declaredHelenGurleyBrowninher1962bestsellerSexandtheSingle
A、AGooglemanagerissupportingtheadvancementofAI.B、TheWatsonsupercomputerhasdefeatedthegreatestplayersofJeopardy
TheEarthcomprisesthreeprincipallayers:thedense,iron-richcore,themantlemadeofsilicate(硅酸盐)thataresemi-moltenat
TheEarthcomprisesthreeprincipallayers:thedense,iron-richcore,themantlemadeofsilicate(硅酸盐)thataresemi-moltenat
随机试题
下列哪一项不属于第一次工业革命时期的科学发现和成就?()
简述工资集体协商的内容。
在我国,为人民服务作为一种多层次、多形式的道德规范是【】
A.髋关节屈曲,内收,内旋,短缩畸形B.髋关节屈曲,外展,外旋畸形C.髋关节屈曲,外旋45°畸形D.髋关节屈曲,内收,外旋,短缩畸形E.髋关节屈曲,外旋90°畸形股骨粗隆间骨折的髋关节畸形是
甲基汞进入机体后的靶器官是()。
乳痈初起,证属肝气不舒,胃热壅滞。内治应首选
Excel中,创建公式的方式包括()。
8月,某市财政局对甲公司执行《会计法》的情况进行检查,发现存在如下事项:(1)为充实会计科力量,公司从外地招聘了一名会计人员李某,李某持有外地的会计从业资格证书,其相关的会计从业资格业务档案尚未调入该公司所在地财政部门.经查李某的会计从业资格业务档案调离
下列应通过“资产减值损失”科目核算的有()。
有一个整数,用它分别去除157、234和324,得到的三个余数之和是100。求这个整数。
最新回复
(
0
)