考研优美英语作文的背诵014
<p> <span word="The">The</span> <span word="preservation">preservation</span> <span word="of">of</span> <span word="embryos">embryos</span> <span word="and">and</span> <span word="juveniles">juveniles</span> <span word="is">is</span> <span word="a">a</span> <span word="rate">rate</span> <span word="occurrence">occurrence</span> <span word="in">in</span> <span word="thefossil">thefossil</span> <span word="record">record</span>. <span word="The">The</span> <span word="tiny">tiny</span>, <span word="delicate">delicate</span> <span word="skeletons">skeletons</span> <span word="are">are</span> <span word="usually">usually</span> <span word="scattered">scattered</span> <span word="byscavengers">byscavengers</span> <span word="or">or</span> <span word="destroyed">destroyed</span> <span word="by">by</span> <span word="weathering">weathering</span> <span word="before">before</span> <span word="they">they</span> <span word="can">can</span> <span word="be">be</span> <span word="fossilized">fossilized</span>.</p><p> <span word="Ichthyosaurs">Ichthyosaurs</span> <span word="had">had</span> <span word="a">a</span> <span word="higher">higher</span> <span word="chance">chance</span> <span word="of">of</span> <span word="being">being</span> <span word="preserved">preserved</span> <span word="than">than</span> <span word="did">did</span> <span word="terrestrial">terrestrial</span> <span word="creatures">creatures</span> <span word="because">because</span>, <span word="as">as</span> <span word="marine">marine</span> <span word="animals">animals</span>, <span word="theytended">theytended</span> <span word="to">to</span> <span word="live">live</span> <span word="in">in</span> <span word="environments">environments</span> <span word="less">less</span> <span word="subject">subject</span> <span word="to">to</span> <span word="erosion">erosion</span>. <span word="Still">Still</span>, <span word="their">their</span> <span word="fossilizationrequired">fossilizationrequired</span> <span word="a">a</span> <span word="suite">suite</span> <span word="of">of</span> <span word="factors">factors</span>: <span word="a">a</span> <span word="slow">slow</span> <span word="rate">rate</span> <span word="of">of</span> <span word="decay">decay</span> <span word="of">of</span> <span word="soft">soft</span> <span word="tissues">tissues</span>, <span word="little">little</span> <span word="scavenging">scavenging</span> <span word="by">by</span> <span word="other">other</span> <span word="animals">animals</span>, <span word="a">a</span> <span word="lack">lack</span> <span word="of">of</span> <span word="swiftcurrents">swiftcurrents</span> <span word="and">and</span> <span word="waves">waves</span> <span word="to">to</span> <span word="jumble">jumble</span> <span word="and">and</span> <span word="carry">carry</span> <span word="away">away</span> <span word="small">small</span> <span word="bones">bones</span>, <span word="and">and</span> <span word="fairly">fairly</span> <span word="rapid">rapid</span> <span word="burial">burial</span>. <span word="Given">Given</span> <span word="these">these</span> <span word="factors">factors</span>, <span word="some">some</span> <span word="areas">areas</span> <span word="have">have</span> <span word="become">become</span> <span word="a">a</span> <span word="treasury">treasury</span> <span word="of">of</span> <span word="well">well</span>-<span word="preserved">preserved</span> <span word="ichthyosaurfossils">ichthyosaurfossils</span>.</p><p> <span word="The">The</span> <span word="deposits">deposits</span> <span word="at">at</span> <span word="Holzmaden">Holzmaden</span>, <span word="Germany">Germany</span>, <span word="present">present</span> <span word="an">an</span> <span word="interesting">interesting</span> <span word="case">case</span> <span word="for">for</span> <span word="analysis">analysis</span>. <span word="Theichthyosaur">Theichthyosaur</span> <span word="remains">remains</span> <span word="are">are</span> <span word="found">found</span> <span word="in">in</span> <span word="black">black</span>, <span word="bituminous">bituminous</span> <span word="marine">marine</span> <span word="shales">shales</span> <span word="depositedabout">depositedabout</span> 190 <span word="million">million</span> <span word="years">years</span> <span word="ago">ago</span>. <span word="Over">Over</span> <span word="the">the</span> <span word="years">years</span>, <span word="thousands">thousands</span> <span word="of">of</span> <span word="specimensof">specimensof</span> <span word="marine">marine</span> <span word="reptiles">reptiles</span>, <span word="fish">fish</span> <span word="and">and</span> <span word="invertebrates">invertebrates</span> <span word="have">have</span> <span word="been">been</span> <span word="recovered">recovered</span> <span word="from">from</span> <span word="theserocks">theserocks</span>. <span word="The">The</span> <span word="quality">quality</span> <span word="of">of</span> <span word="preservation">preservation</span> <span word="is">is</span> <span word="outstanding">outstanding</span>, <span word="but">but</span> <span word="what">what</span> <span word="is">is</span> <span word="evenmore">evenmore</span> <span word="impressive">impressive</span> <span word="is">is</span> <span word="the">the</span> <span word="number">number</span> <span word="of">of</span> <span word="ichthyosaur">ichthyosaur</span> <span word="fossils">fossils</span> <span word="containing">containing</span> <span word="preserved">preserved</span> <span word="embryos">embryos</span>.</p><p> <span word="Ichthyosaurswith">Ichthyosaurswith</span> <span word="embryos">embryos</span> <span word="have">have</span> <span word="been">been</span> <span word="reported">reported</span> <span word="from">from</span> 6 <span word="different">different</span> <span word="levels">levels</span> <span word="of">of</span> <span word="the">the</span> <span word="shale">shale</span> <span word="in">in</span> <span word="a">a</span> <span word="smallarea">smallarea</span> <span word="around">around</span> <span word="Holzmaden">Holzmaden</span>, <span word="suggesting">suggesting</span> <span word="that">that</span> <span word="a">a</span> <span word="specific">specific</span> <span word="site">site</span> <span word="was">was</span> <span word="used">used</span> <span word="bylarge">bylarge</span> <span word="numbers">numbers</span> <span word="of">of</span> <span word="ichthyosaurs">ichthyosaurs</span> <span word="repeatedly">repeatedly</span> <span word="over">over</span> <span word="time">time</span>. <span word="The">The</span> <span word="embryos">embryos</span> <span word="are">are</span> <span word="quiteadvanced">quiteadvanced</span> <span word="in">in</span> <span word="their">their</span> <span word="physical">physical</span> <span word="development">development</span>; <span word="their">their</span> <span word="paddles">paddles</span>, <span word="for">for</span> <span word="example">example</span>, <span word="arealready">arealready</span> <span word="well">well</span> <span word="formed">formed</span>. <span word="One">One</span> <span word="specimen">specimen</span> <span word="is">is</span> <span word="even">even</span> <span word="preserved">preserved</span> <span word="in">in</span> <span word="the">the</span> <span word="birth">birth</span> <span word="canal">canal</span>. <span word="Inaddition">Inaddition</span>, <span word="the">the</span> <span word="shale">shale</span> <span word="contains">contains</span> <span word="the">the</span> <span word="remains">remains</span> <span word="of">of</span> <span word="many">many</span> <span word="newborns">newborns</span> <span word="that">that</span> <span word="are">are</span> <span word="between">between</span> 20<span word="and">and</span> 30 <span word="inches">inches</span> <span word="long">long</span>.</p>
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