gre考试阅读真题解析(A)
<p> <span word="Because">Because</span> <span word="of">of</span> <span word="its">its</span> <span word="accuracy">accuracy</span> <span word="in">in</span> <span word="outlining">outlining</span> <span word="the">the</span> <span word="Earths">Earths</span> <span word="subsurface">subsurface</span>, <span word="the">the</span> <span word="seismic">seismic</span>-<span word="reflection">reflection</span> <span word="method">method</span> <span word="remains">remains</span> <span word="the">the</span> <span word="most">most</span> <span word="important">important</span> <span word="tool">tool</span> <span word="in">in</span> <span word="the">the</span> <span word="search">search</span> <span word="for">for</span> <span word="petroleum">petroleum</span> <span word="reserves">reserves</span> . <span word="In">In</span> <span word="field">field</span> <span word="practice">practice</span>, <span word="a">a</span> <span word="subsurface">subsurface</span> <span word="is">is</span> <span word="mapped">mapped</span> <span word="by">by</span> <span word="arranging">arranging</span> <span word="a">a</span> <span word="series">series</span> <span word="of">of</span> <span word="wave">wave</span>-<span word="train">train</span> <span word="sources">sources</span>, <span word="such">such</span> <span word="as">as</span> <span word="small">small</span> <span word="dynamite">dynamite</span> <span word="explosions">explosions</span>, <span word="in">in</span> <span word="a">a</span> <span word="grid">grid</span> <span word="pattern">pattern</span>. <span word="As">As</span> <span word="each">each</span> <span word="source">source</span> <span word="is">is</span> <span word="activated">activated</span>, <span word="it">it</span> <span word="generates">generates</span> <span word="a">a</span> <span word="wave">wave</span> <span word="train">train</span> <span word="that">that</span> <span word="moves">moves</span> <span word="downward">downward</span> <span word="at">at</span> <span word="a">a</span> <span word="speed">speed</span> <span word="determined">determined</span> <span word="uniquely">uniquely</span> <span word="by">by</span> <span word="the">the</span> <span word="rocks">rocks</span> <span word="elastic">elastic</span> <span word="characteristics">characteristics</span>. <span word="As">As</span> <span word="rock">rock</span> <span word="interfaces">interfaces</span> <span word="are">are</span> <span word="crossed">crossed</span>, <span word="the">the</span> <span word="elastic">elastic</span> <span word="characteristics">characteristics</span> <span word="encountered">encountered</span> <span word="generally">generally</span> <span word="change">change</span> <span word="abruptly">abruptly</span>, <span word="which">which</span> <span word="causes">causes</span> <span word="part">part</span> <span word="of">of</span> <span word="the">the</span> <span word="energy">energy</span> <span word="to">to</span> <span word="be">be</span> <span word="reflected">reflected</span> <span word="back">back</span> <span word="to">to</span> <span word="the">the</span> <span word="surface">surface</span>, <span word="where">where</span> <span word="it">it</span> <span word="is">is</span> <span word="recorded">recorded</span> <span word="by">by</span> <span word="seismic">seismic</span> <span word="instruments">instruments</span>. <span word="The">The</span> <span word="seismic">seismic</span> <span word="records">records</span> <span word="must">must</span> <span word="be">be</span> <span word="processed">processed</span> <span word="to">to</span> <span word="correct">correct</span> <span word="for">for</span> <span word="positional">positional</span> <span word="differences">differences</span> <span word="between">between</span> <span word="the">the</span> <span word="source">source</span> <span word="and">and</span> <span word="the">the</span> <span word="receiver">receiver</span>, <span word="for">for</span> <span word="unrelated">unrelated</span> <span word="wave">wave</span> <span word="trains">trains</span>, <span word="and">and</span> <span word="for">for</span> <span word="multiple">multiple</span> <span word="reflections">reflections</span> <span word="from">from</span> <span word="the">the</span> <span word="rock">rock</span> <span word="interfaces">interfaces</span>. <span word="Then">Then</span> <span word="the">the</span> <span word="data">data</span> <span word="acquired">acquired</span> <span word="at">at</span> <span word="each">each</span> <span word="of">of</span> <span word="the">the</span> <span word="specific">specific</span> <span word="source">source</span> <span word="locations">locations</span> <span word="are">are</span> <span word="combined">combined</span> <span word="to">to</span> <span word="generate">generate</span> <span word="a">a</span> <span word="physical">physical</span> <span word="profile">profile</span> <span word="of">of</span> <span word="the">the</span> <span word="subsurface">subsurface</span>, <span word="which">which</span> <span word="can">can</span> <span word="eventually">eventually</span> <span word="be">be</span> <span word="used">used</span> <span word="to">to</span> <span word="select">select</span> <span word="targets">targets</span> <span word="for">for</span> <span word="drilling">drilling</span>.</p><p> 17. <span word="The">The</span> <span word="passage">passage</span> <span word="is">is</span> <span word="primarily">primarily</span> <span word="concerned">concerned</span> <span word="with">with</span></p><p> <span word="describing">describing</span> <span word="an">an</span> <span word="important">important</span> <span word="technique">technique</span></p><p> <span word="discussing">discussing</span> <span word="a">a</span> <span word="new">new</span> <span word="method">method</span></p><p> <span word="investigating">investigating</span> <span word="a">a</span> <span word="controversial">controversial</span> <span word="procedure">procedure</span></p><p> <span word="announcing">announcing</span> <span word="a">a</span> <span word="significant">significant</span> <span word="discovery">discovery</span></p><p> <span word="promoting">promoting</span> <span word="a">a</span> <span word="novel">novel</span> <span word="application">application</span></p><p> 18. <span word="According">According</span> <span word="to">to</span> <span word="the">the</span> <span word="passage">passage</span>, <span word="in">in</span> <span word="the">the</span> <span word="seismic">seismic</span>-<span word="reflection">reflection</span> <span word="method">method</span> <span word="all">all</span> <span word="of">of</span> <span word="the">the</span> <span word="following">following</span> <span word="have">have</span> <span word="a">a</span> <span word="significant">significant</span> <span word="effect">effect</span> <span word="on">on</span> <span word="the">the</span> <span word="signal">signal</span> <span word="detected">detected</span> <span word="by">by</span> <span word="the">the</span> <span word="seismic">seismic</span> <span word="instruments">instruments</span> <span word="EXCEPT">EXCEPT</span> <span word="the">the</span></p>
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