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
64
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
HalloweenA)OnOctober31st,dozensofchildrendressedincostumesknockontheirneighbors’doorsandyell"TrickorTreat
HalloweenA)OnOctober31st,dozensofchildrendressedincostumesknockontheirneighbors’doorsandyell"TrickorTreat
AnewreportreleasedbytheAmericanFederationofTeachers(AFT)remindsusofatopiceducationwritersalmostneveraddress—th
AnewreportreleasedbytheAmericanFederationofTeachers(AFT)remindsusofatopiceducationwritersalmostneveraddress—th
TheEarthcomprisesthreeprincipallayers:thedense,iron-richcore,themantlemadeofsilicate(硅酸盐)thataresemi-moltenat
Carsandotherroadvehiclesarethesinglemainsourceofharmfulnitrogenoxides.Roadtransportremainsthebiggestsourc
HintsandTipstoSaveMoneyA)Spendless.Thisisnotoversimplifyingthebestwaytosavemoney!Itisessentialifyoua
HintsandTipstoSaveMoneyA)Spendless.Thisisnotoversimplifyingthebestwaytosavemoney!Itisessentialifyoua
A、Loweringtransportationfees.B、Theenvironmentalengineeringclass.C、Theman’scarintheshop.D、Betterenvironment.D对话中女士
随机试题
女性,34岁。1个月来胸骨后烧灼样不适与反酸就诊,反流物呈酸性,胃灼热与反酸常发生在餐后,进食时胸骨后有梗塞感下列哪一项处理是错误的
通常人耳可听到的声波的频率范围是()。
我国()等,已发展成城镇密集区。
构筑物满水试验前必须具备的条件有()。
某公司2012年1月1日经批准发行3年期到期一次还本并按年付息的债券,面值总额为10000000元,票面利率为8%。如果发行时的市场利率为6%,则该债券的发行价格总额为()元。(已知PVA6,3=2.673。PV6,3=0.8396)
影响企业组织结构的最为基本的要素是()。
甲公司为股份有限公司,2014年年初,甲公司发行在外的普通股股票为250万股,面值为1元/股,甲公司期初资本公积余额为110万元(其中其他资本公积70万元,股本溢价40万元),盈余公积为30万元,未分配利润为40万元。2014年7月31日,经股东大会批准,
假定其他条件不变,发生通货膨胀时债权人将受损,而债务人将受益。()
美国传播学家施拉姆提出了决定媒体选择概率的公式,是选择媒体的最优决策的依据。如果某媒体的功效为0,9,需付…的代价为2,则该媒体选择的概率为()。
亚里士多德说:“凡是不凭感情因素治事的统治者总比感情用事的人们较为优良。法律恰是全没有感情的;人类的本性便是谁都难免有感情。”“如果既是贤良为政,那就不会乱法。我们应该注意到邦国虽有良法,要是人民不能全部遵循,仍然不能实现法治。”以下运用法理学进行的分析,
最新回复
(
0
)