首页
登录
职称英语
The Earth comprises three principal layers: the dense, iron-rich core, the m
The Earth comprises three principal layers: the dense, iron-rich core, the m
游客
2024-02-14
45
管理
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 crest 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. [br] The 1 plates of the Earth are formed from ______.
选项
A、the oceanic crusts and continental crests
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
正确理解该句中top和solid并列修饰part,即可知道选项C为该句的同义替换,故正确。
转载请注明原文地址:https://tihaiku.com/zcyy/3450093.html
相关试题推荐
TheEarthcomprisesthreeprincipallayers:thedense,iron-richcore,them
TheEarthcomprisesthreeprincipallayers:thedense,iron-richcore,them
TheEarthcomprisesthreeprincipallayers:thedense,iron-richcore,them
TheEarthcomprisesthreeprincipallayers:thedense,iron-richcore,them
For______footballplayers,injuriesareanoccupationalhazardwhichseemsuna
TheEarthcomprisesthreeprincipallayers:thedense,iron-richcore,them
TheEarthcomprisesthreeprincipallayers:thedense,iron-richcore,them
TheEarthcomprisesthreeprincipallayers:thedense,iron-richcore,them
Theprincipaltechniqueincurrentuseforteachingreadingattheintermedi
Theprincipaltechniqueincurrentuseforteachingreadingattheintermedi
随机试题
Despiteoftheiropposition,hewenthisownwayandstartedhispreparations.A、
[originaltext]A:Rookiedirectortalksabouttacklinggayteenangstandromanc
Thoughtelephoneisindispensableinone’severydaylife,itbringsalotoftro
He(use)______swiminthatriverwhenhewasalittleboy.usedto本题考查固定结构的用法。句子中
TheAmericandreamismost______duringtheperiodsofproductivityandwealthg
A. B. C. D.
Z特殊普通合伙企业的合伙人需要进行产权转让目的的评估,则评估对象是( )。A、该
阅读下面材料,回答问题。 黄某是某区政府机要室的机要员。2009年10月16日
A.增加和减小 B.减少和增大 C.为原来的一半和减小 D.为原来的一倍和
(2013年真题)根据《环境影响评价技术导则-声环境》,下列关于声环境影响预测范
最新回复
(
0
)