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
2016-10-07
27
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://kaotiyun.com/show/IuY7777K
0
大学英语四级
相关试题推荐
Pricesdeterminehowresourcesaretobeused.Theyarealsothemeansbywhichproductsandservicesthatareinlimited【B1】___
Today,studentswhowanttolearnEnglishintheUShaveawidechoiceofcoursesandinstitutionsto【B1】_______.And,becauset
Weoftenpassonlittlebitsofinformationtoourchildren,notknowingiftheyaretrue,andonlybecausetheywere【B1】_______
Americansbelievethatindividualsmustlearnto【B1】_______themselvesorrisklosingfreedom.Thismeansachievingbothfinanci
Americansbelievethatindividualsmustlearnto【B1】_______themselvesorrisklosingfreedom.Thismeansachievingbothfinanci
Crimeisincreasingworldwide.Thereiseveryreasontobelievethe【B1】_____willcontinuethroughthenextfewdecades.Crimera
Crimeisincreasingworldwide.Thereiseveryreasontobelievethe【B1】_____willcontinuethroughthenextfewdecades.Crimera
A、Theygenerallyholdbadfeelingstowardstheirbirthparents.B、Theydonotwanttohurtthefeelingsoftheiradoptiveparent
Roll-CallSystemonCampus1.“点名制度”在大学中一直被老师们使用2.学生们对此褒贬不一3.在我看来……
TheEarthcomprisesthreeprincipallayers:thedense,iron-richcore,themantlemadeofsilicate(硅酸盐)thataresemi-moltenatd
随机试题
住宅中插座回路用剩余电流(漏电)保护,其动作电流为下列哪个数值?[2008年第108题]
A.邪气阻隔,脉道不通B.冲任失养,拘急而痛C.瘀血内阻,新血不守D.胞宫寒冷,血瘀冲任E.冲任瘀阻,气血运行不畅
A、血栓栓塞B、脂肪栓塞C、空气栓塞D、羊水栓塞E、肿瘤栓塞股骨干骨折
以下不是脂质体的制备方法的是
当设备已有施工图纸、在安装现场制作的非标准设备,其合同的价格应按( )确定。
高某因犯伤害罪而被判处有期徒刑5年,刑满释放后第4年又因盗窃罪被判处有期徒刑3年。在此情况下,()不能对高某适用。
教师引导学生选择有针对性的格言作为座右铭以自励、自律,使其获得教益的德育方法是()。
2016年2月,关于人类首次直接探测到了引力波的话题轰动世界。下列关于引力波的说法正确的是()。
A、 B、 C、 D、 A
ManyAsiantouristsdarenotgotoThailandsincethetsunamiin2004becauseoftheir______.Privatecompanieshavebeengran
最新回复
(
0
)