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
56
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.
The 15 plates of the Earth are formed from _____.
选项
A、the oceanic crusts and continental crusts
B、the crusts and the mantle
C、the crusts and the top and solid part of the mantle
D、the continental crusts and the solid part of the mantle
答案
C
解析
推理判断题。此题可定位到第1段倒数第3句。题干中的15 plates是原文该句中的宾语,且该句的谓语中心词是consist of(由……组成),题干的谓语是are formed from,这意思一致,但题目用的是被动语态,表明答案可从原文该句的主语得到。主语中的top和solid并列修饰part of the mantle。选项C为该句的同义替换,故正确。
转载请注明原文地址:https://kaotiyun.com/show/7I47777K
0
大学英语四级
相关试题推荐
InonlytwodecadesAsianAmericanshavebecomethefastest-growingU.S.minority.Astheirchildrenbeganmovingupthroughthe
HintsandTipstoSaveMoneyA)Spendless.Thisisnotoversimplifyingthebestwaytosavemoney!Itisessentialifyouar
HintsandTipstoSaveMoneyA)Spendless.Thisisnotoversimplifyingthebestwaytosavemoney!Itisessentialifyouar
AnewreportreleasedbytheAmericanFederationofTeachers(AFT)remindsusofatopiceducationwritersalmostneveraddress—th
TheEarthcomprisesthreeprincipallayers:thedense,iron-richcore,themantlemadeofsilicate(硅酸盐)thataresemi-moltenat
HintsandTipstoSaveMoneyA)Spendless.Thisisnotoversimplifyingthebestwaytosavemoney!Itisessentialifyoua
HintsandTipstoSaveMoneyA)Spendless.Thisisnotoversimplifyingthebestwaytosavemoney!Itisessentialifyoua
A、Loweringtransportationfees.B、Theenvironmentalengineeringclass.C、Theman’scarintheshop.D、Betterenvironment.D对话中女士
2013年10月30日,中国第一所网络文学大学(onlineliteratureuniversity)成立。诺贝尔文学奖得主(NobelLiteraturePrizeLaureate)莫言担任名誉校长(honoraryprincipal).该大
TheEarthcomprisesthreeprincipallayers:thedense,iron-richcore,themantlemadeofsilicate(硅酸盐)thataresemi-moltenat
随机试题
甲和乙共同实施拐卖妇女、儿童罪,均被判处死刑立即执行。最高法院复核后认为全案判决认定事实正确,甲系主犯应当判处死刑立即执行,但对乙可不立即执行。关于最高法院对此案的处理,下列哪一选项是正确的?()
管道组对前,需将管端的局部凹凸、椭圆等变形进行修正。
对消费者的购买行为具有最广泛、最深远影响的因素是()
某企业2010年可比产品按上年实际平均单位成本计算的本年累计总成本为3200万元,按本年计划单位成本计算的本年累计总成本为3100万元,本年累计实际总成本为3050万元。则可比产品成本的降低额为()万元。
投射效应指在认知和对他人形成印象时,以为他人也具备与自己相似的特性的现象,即推己及人的情形。根据上述定义,下列不属于投射效应的是:
现有浓度为10%的盐水200克,再加人多少克浓度为30%的盐水,可以得到浓度为22%的盐水?
TheTreasurycouldpocket20millionayearinextrafinesoncethecountry’sspeedcameranetworkisexpanded.Motoringorgani
在交换机配置模式下,使用命令vtppruning可以启动VTP动态修剪功能。以太网介质访问控制策略可以采用不同的监听算法,其中一种是:“一旦介质空闲就发送数据,假如介质忙,继续监听,直至介质空闲后立即发送数据”,这种算法称为(62)监听算法,该算法的主要特
假设职员表已在当前工作区打开,其当前记录的“姓名”字段值为“李彤”(C型字段)。在命令窗口输入并执行如下命令:姓名=姓-’’出勤’’?姓名屏幕上会显示
Tenyearsago,JoeAllenbeganstudyingadiversegroupofseventhgradersneartheUniversityofVirginia,wherehe’saprofess
最新回复
(
0
)