2015年职称英语理工类完形填空基础练习题(3)
<p> <span word="Earths">Earths</span> <span word="Inner">Inner</span> <span word="Core">Core</span></p><p> <span word="Scientists">Scientists</span> <span word="have">have</span> <span word="long">long</span> <span word="struggled">struggled</span> <span word="to">to</span> <span word="understand">understand</span> <span word="what">what</span> <span word="lies">lies</span> <span word="at">at</span> <span word="the">the</span> <span word="planets">planets</span> <span word="center">center</span>. <span word="Direct">Direct</span> <span word="observation">observation</span> <span word="of">of</span> <span word="its">its</span> <span word="center">center</span> <span word="is">is</span> <span word="impossible">impossible</span>, <span word="so">so</span> <span word="researchers">researchers</span> <span word="must">must</span> <span word="to">to</span> <span word="other">other</span> <span word="evidence">evidence</span>.</p><p> <span word="In">In</span> 1889, <span word="a">a</span> <span word="German">German</span> <span word="scientist">scientist</span> <span word="detected">detected</span> <span word="a">a</span> <span word="severe">severe</span> <span word="earthquake">earthquake</span> <span word="in">in</span> <span word="Japan">Japan</span>. <span word="Geophysicists">Geophysicists</span> <span word="concluded">concluded</span> <span word="that">that</span> <span word="shock">shock</span> <span word="waves">waves</span> <span word="jolts">jolts</span> <span word="from">from</span> <span word="one">one</span> <span word="side">side</span> <span word="of">of</span> <span word="Earth">Earth</span> <span word="through">through</span> <span word="the">the</span> <span word="center">center</span> <span word="to">to</span> <span word="the">the</span> <span word="other">other</span> <span word="side">side</span>. <span word="Then">Then</span> <span word="in">in</span> 1936, <span word="Danish">Danish</span> <span word="geophysicist">geophysicist</span> <span word="Inge">Inge</span> <span word="Lehmann">Lehmann</span> <span word="studied">studied</span> <span word="the">the</span> <span word="waves">waves</span> <span word="to">to</span> <span word="determine">determine</span> <span word="that">that</span> <span word="within">within</span> <span word="Earths">Earths</span> <span word="core">core</span> <span word="of">of</span> <span word="molten">molten</span> <span word="iron">iron</span> <span word="lies">lies</span> <span word="a">a</span> <span word="solid">solid</span> <span word="inner">inner</span> <span word="core">core</span> - <span word="but">but</span> <span word="that">that</span> <span word="core">core</span> <span word="was">was</span> <span word="made">made</span> <span word="of">of</span> <span word="eluded">eluded</span> <span word="her">her</span>. <span word="Other">Other</span> <span word="geophysicists">geophysicists</span> <span word="quickly">quickly</span> <span word="determined">determined</span> <span word="that">that</span> <span word="Lehmanns">Lehmanns</span> <span word="inner">inner</span> <span word="core">core</span> <span word="was">was</span> <span word="composed">composed</span> <span word="mostly">mostly</span> <span word="iron">iron</span>. <span word="Since">Since</span> <span word="then">then</span>, <span word="Lehmanns">Lehmanns</span> <span word="discovery">discovery</span> <span word="has">has</span> <span word="conventional">conventional</span> <span word="Earth">Earth</span> <span word="science">science</span>.</p><p> <span word="But">But</span> <span word="now">now</span> <span word="scientists">scientists</span> <span word="are">are</span> <span word="challenging">challenging</span> <span word="traditional">traditional</span> <span word="theory">theory</span> <span word="with">with</span> <span word="new">new</span> <span word="and">and</span> <span word="radical">radical</span> . <span word="For">For</span> <span word="example">example</span>, <span word="Earths">Earths</span> <span word="center">center</span> <span word="could">could</span> <span word="actually">actually</span> <span word="contain">contain</span> <span word="an">an</span> <span word="inner">inner</span> <span word="core">core</span> <span word="within">within</span> <span word="the">the</span> <span word="inner">inner</span> <span word="core">core</span>, <span word="claim">claim</span> <span word="Ishii">Ishii</span> <span word="and">and</span> <span word="colleague">colleague</span> <span word="Adam">Adam</span> <span word="Dziewonski">Dziewonski</span>.</p><p> <span word="Analyzing">Analyzing</span> <span word="hundreds">hundreds</span> <span word="of">of</span> <span word="thousands">thousands</span> <span word="of">of</span> <span word="earthquake">earthquake</span> <span word="wave">wave</span> , <span word="they">they</span> <span word="maintain">maintain</span> <span word="that">that</span> <span word="the">the</span> <span word="inner">inner</span> <span word="core">core</span> <span word="has">has</span> <span word="at">at</span> <span word="its">its</span> <span word="heart">heart</span> <span word="a">a</span> <span word="tiny">tiny</span>, <span word="even">even</span> <span word="more">more</span> <span word="solid">solid</span> <span word="sphere">sphere</span> . <span word="This">This</span> <span word="sphere">sphere</span> <span word="may">may</span> <span word="be">be</span> <span word="the">the</span> <span word="oldest">oldest</span> <span word="fossil">fossil</span> <span word="from">from</span> <span word="the">the</span> <span word="formation">formation</span> <span word="of">of</span> <span word="Earth">Earth</span>, <span word="says">says</span> <span word="Dziewonski">Dziewonski</span>.</p><p> <span word="Dziewonski">Dziewonski</span> <span word="and">and</span> <span word="Ishii">Ishii</span> <span word="speculate">speculate</span> <span word="that">that</span> <span word="shortly">shortly</span> <span word="Earth">Earth</span> <span word="formed">formed</span> <span word="around">around</span> 4.8 <span word="billion">billion</span> <span word="years">years</span> <span word="ago">ago</span>, <span word="a">a</span> <span word="giant">giant</span> <span word="asteroid">asteroid</span> <span word="smashed">smashed</span> <span word="into">into</span> <span word="the">the</span> <span word="young">young</span> <span word="planet">planet</span> <span word="and">and</span> <span word="nearly">nearly</span> <span word="melted">melted</span> <span word="it">it</span>. <span word="But">But</span> <span word="Earths">Earths</span> <span word="center">center</span> <span word="didnt">didnt</span> <span word="quite">quite</span> <span word="melt">melt</span>; <span word="it">it</span> <span word="mass">mass</span> <span word="as">as</span> <span word="the">the</span> <span word="planet">planet</span> <span word="cooled">cooled</span>. <span word="The">The</span> <span word="core">core</span> <span word="within">within</span> <span word="a">a</span> <span word="core">core</span> <span word="may">may</span> <span word="be">be</span> <span word="the">the</span> <span word="kernel">kernel</span> <span word="that">that</span> <span word="endured">endured</span>. <span word="Its">Its</span> <span word="presence">presence</span> <span word="could">could</span> <span word="change">change</span> <span word="our">our</span> <span word="basic">basic</span> <span word="ideas">ideas</span> <span word="about">about</span> <span word="the">the</span> <span word="of">of</span> <span word="the">the</span> <span word="planet">planet</span>, <span word="Dziewonski">Dziewonski</span> <span word="says">says</span>.</p>
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