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
2023-07-01
14
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 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. [br] 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
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。C为该句的同义替换,故正确。
转载请注明原文地址:https://www.tihaiku.com/zcyy/2798953.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
TheEarthcomprisesthreeprincipallayers:thedense,iron-richcore,them
TheEarthcomprisesthreeprincipallayers:thedense,iron-richcore,them
TheEarthcomprisesthreeprincipallayers:thedense,iron-richcore,them
TheEarthcomprisesthreeprincipallayers:thedense,iron-richcore,them
TheEarthcomprisesthreeprincipallayers:thedense,iron-richcore,them
TheEarthcomprisesthreeprincipallayers:thedense,iron-richcore,them
随机试题
Theygotooneoftheworld’smostprestigiousuniversitiesandpridethemse
[originaltext]Foryears,childrenintheindustrialareasofEuropeandAme
甲、乙类生产厂房中下列哪一种空气循环方式是正确的?A.允许20%空气量循环 B
设有一个员工关系EMP(员工号,姓名,部门名,职位,薪资),若需查询不同部门中担
教师在讲授《童年》一课时,这样介绍主人公:他是一个被遗弃的孩子,“我”的外祖母将
治疗肺痨之阴阳两虚证,应首选的方剂是()A.秦艽鳖甲散 B.月华丸 C
作为由若干独立企业法人所组成的集合体,企业集团的联结纽带是()。A.产品
桂枝合剂的药物组成是A.桂枝、赤芍、生姜、大枣、甘草 B.桂枝、白芍、生姜、大
某项目的原始投资额现值为2500万元,现值指数为1.6,则净现值为( )万元。A
资格审查方法分为合格制和有限数量制两种,两者的区别主要体现在()。A.审查程序
最新回复
(
0
)