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 d
The Earth comprises three principal layers: the dense, iron-rich core, the mantle made of silicate(硅酸盐)that are semi-molten at d
admin
2016-09-21
78
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.
This passage is probably _____.
选项
A、a newspaper advertisement
B、a chapter of a novel
C、an excerpt from a textbook
D、a scientific report of new findings
答案
C
解析
由本文的语言风格和描述内容可以判定这篇文章既不是商业性的,也不是文学性的,同时文中叙述的内容具有科普性质,不可能是太前沿性的,因此A、B、D三项都不正确,C为此题答案。
转载请注明原文地址:https://kaotiyun.com/show/2tY7777K
0
大学英语四级
相关试题推荐
PromoteLearningandSkillsforYoungPeopleandAdultsA)Thisgoalplacestheemphasisonthelearningneedsofyoungpeoplean
TheArtofFriendshipA)OneeveningafewyearsagoIfoundmyselfinananxiety.Nothingwasreallywrong—myfamilyandIwer
Today,studentswhowanttolearnEnglishintheUShaveawidechoiceofcoursesandinstitutionsto【B1】______from.And,becaus
Doyoufindgettingupinthemorningsodifficultthatit’spainful?Thismightbecalledlaziness,butDr.Kleitmanhasanew
It’sdifficulttoimaginetheseaeverrunningoutoffish.It’ssovast,sodeep,so【B1】______.Unfortunately,it’snot【B2】____
UniversitiesBranchOutA)Asneverbeforeintheirlonghistory,universitieshavebecomeinstrumentsofnationalcompetitionas
UniversitiesBranchOutA)Asneverbeforeintheirlonghistory,universitieshavebecomeinstrumentsofnationalcompetitionas
AboutoneintwentyadultsintheUnitedStatescannotreadEnglish.Anewfederalstudyshowsthatadultsmadelittleprogress
Afewdegreescanmakeabigdifferencewhenitcomestofoodstorage.Foodscangobadiftheygettoowarm.Butformanyofth
随机试题
小儿五脏六腑的形气不足主要体现在
A.聚氧乙烯脱水山梨醇脂肪酸酯B.洁尔灭C.卵磷脂D.磺酸化物E.苯甲酸类非离子型表面活性剂()。
招标人采取邀请招标方式的,应当向()家以上物业管理企业发出投标邀请书。
张某报名参加导游资格考试后,尚未取得导游资格证就与某旅行社联系,希望参加旅行社的导游实习,今年9月正值旅游旺季,该旅行社导游人员不够,就聘用张某充任导游人员,被旅游行政管理部门查获,以其未经导游资格考试合格,擅自进行导游活动给予了罚款处罚。张某对处罚不服,
根据修改的个人所得税法规定:自2011年9月1日起,个税工薪所得费用减除标准(即起征点)由2000元/月提高到3500元/月。这一调整将有利于()。①扩大征税范围②调节个人收入分配③增加财政收入④促进公平分配
某地政府开放了单位食堂,邀请附近居民和农民工到机关食堂就餐,这不仅方便了居民,而且也增加了干群交流的机会,获得好评。对此,你怎么看?
清朝末期,五位大臣国外考察后上书建议进行预备立宪,认为立宪有哪些好处()
除非遇到机会同时又有能力,否则不可能成功。这就是成功的奥秘。在成功人士中找不到反例。以下哪项最符合题干的断定?
Sometimeswehavespecificproblemswithourmother;sometimes,lifewithhercanjustbehardwork.Iftherearedifficultiesi
沟通是项目管理的一项重要工作,下图为人与人之间的沟通模型。该模型说明了发送者收集信息、对信息加工处理、通过通道传送、接受者接收并理解、接受者反馈等若干环节。由于人们的修养不同和表达能力的差别,在沟通时会产生各种各样的障碍。语义障碍最常出现在(255),认知
最新回复
(
0
)