2017年12月英语四级阅读考前练习：地理环境

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　　Scattered around the globe are more than 100 smallregions of isolated
volcanic activity known togeologists as hot spots. Unlike most of the
world'svolcanoes. they are not always found at theboundaries of the great
drifting plates that make upthe earth's surface; on the contrary, many of
chemlie deep in the interior of a plate. Most of the hot spots move only slowly,
and in some cases themovement of the plates past them has left trails of dead
volcanoes. The bot spots and theirvolcanic trails are milestones that mark the
passage of the plates.
        　　That the plates are moving is now beyond dispute. Africa and South America.
for example. aremoving away from each other as new material is injected into the
sea floor between them. Thecomplementary coastlines and certain geological
features that seem to span the ocean arereminders of where the two continents
were once joined. The relative motion of the platescarrying these continents has
been constructed in detail, but the motion of one plate withrespect to another
cannot readily be translated into motion with respect to the earth’s interior.
It is not possible to determine whether both continents are moving in opposite
directions orwhether one continent is stationary and the other is drifting away
from it. Hot spots. anchoredin the deeper layers of the earth, provide the
measuring instruments needed to resolve thequestion. From an analysis of the
hot-spot population it appears that the African plate isstationary and that it
has not moved during the past 30 million years.
        　　The significance of hot spots is not confined lo their role as a frame of
reference. It nowappears that they also have an important influence on the
geophysical processes chat propelthe plates across the globe. When a continental
plate comes to rest over a hot spot. thematerial rising from deeper layer
creates a broad dome. As the dome grows, it develops deepfissures (cracks); in
at least a few cases the continent may break entirely along some of
thesefissures, so that the hoc spot initiates the formation of a new ocean. Thus
just as earliertheories have explained the mobility of the continents, so hot
spots may explain theirmutability (inconstancy).
        　　1.We can learn from che first paragraphthat_____________.
        　　A. there are no volcanic activities on hoc spots
        　　B. most hoc spots are located in the inner part of aplate
        　　C. hot spots usually lie. at che boundaries of drifting plates;
        　　D. the passage of plates through hot spots will leave dead volcanoes
        　　2.The author believes that_____________.
        　　A) the motion of the plates corresponds to thar of the earth's interior
        　　B) the geological theory about drifting plates has been proved to be
true
        　　C) the hot spots and the plates move slowly in opposite directions
        　　D) the movement of hot spots proves the continents are moving apart
        　　3.That Africa and South America were once joined can be deduced from the
factthat_________.
        　　A) the two continents are still moving in opposite directions
        　　B) they have been found to share certain geological features
        　　C) the African plate has been stable for 30 million years
        　　D) over 100 hot spots are scattered all around the globe
        　　4.The hot spot theory may prove useful in explaining__________.
        　　A) the structure of the African plates.
        　　B) the revival of dead volcanoes.
        　　C) the mobility of the continents.
        　　D) the formation of new oceans.
            
            

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        　　5.The passage is mainly about______________.
        　　A) the features of volcanic activities
        　　B) the importance of the theory about drifting plates
        　　C) the significance of hot spots in geophysical studies
        　　D) the process of the formation of volcanoes
        　　1.从文章第一段我们可以知道，_____________。
        　　A)在热点没有火山活动
        　　B)大多数的热点位于板块内部
        　　C)热点通常位于漂移板块的边界处
        　　D)板块经过热点后会留下死火山
        　　[B]根据题干直接查找到第1段。第2句第2个分句提到“其中很多位于板块内部的深处”，而表达同样含义的是B选项。该段第1句指出，这些互不相连、发生火山运动的小地区，地质学家称之为热点，可见A项错误。选项C与第2句第1个分句的内容相反。倒数第2句提到“在某些情形下，板块移动经过热点留下死火山的痕迹”，即不是所有板块移动都会留下死火山的痕迹，故D错。
        　　2.作者相信______________。
        　　A)板块运动与地球内部是一致的
        　　B)若干漂移板块的地质学理论被证明是正确的
        　　C)热点与板块向相反方向缓慢移动
        　　D)热点的移动证明了大陆在相互远离
        　　[B]文章第2段的开头指出That the plates are moving is now beyond dispute。beyond
dispute意为“毋庸置疑”，故答案选B项。从第2段第4句的“但是一个板块相对于另外一个板块的运动不能被顺理成章地解释成板块与它相对于地球内部的运动”，可排除A项。
        　　3.可以从_________________的事实，推断非洲和南美洲曾经是连接在一起的。
        　　A)两个洲仍然向相反方向移动
        　　B)人们发现两个洲拥有某些共同的地质特征
        　　B)非洲板块3千万年来一直保持稳定
        　　D)超过100个热点散步在全球
        　　[B]从第2段的第3句可知，非洲和南美洲曾经连接在一起的证据有两个——海岸线所具有的互补的特征(complementary
coastlines)及某些地质特点(certain geological features)。B项符合后者，故为正确答案。
        　　4.热点理论可能在解释___________时被证明是有用的。
        　　A)非洲板块的结构
        　　B)死火山的复活
        　　C)大洲的可动性
        　　D)新海洋的形戒
        　　[D]关于hot spot theory的作用，除了第2段提到的参照作用外，第3段论及的另一个重要作用在于它能够推动扳块在地球表面漂移(propel
the plates across the globe)，从而引发了新海洋的形成(initiates theformation of a new
ocean)。故答案选D项。
        　　5.文章主要是关于_______________。
        　　A)火山活动的特征
        　　B)漂移板块理论的重要性
        　　C)热点在地理物理学研究中的意义
        　　D)火山形成的过程
        　　[C]全文三个段落主要是围绕“热点对于地球物理学研究的意义”而展开的。故答案选C项。全篇共三段，第l段讲的是hot
spots的定义与分布，第2段讲hot spots在大陆板块移动中的参照作用，第3段讲hot spots引起新海洋形成的地球物理意义。