综合类职称英语A级考试的阅读精练试题(2)
<p> <span word="Clever">Clever</span> <span word="genetic">genetic</span> <span word="detective">detective</span> <span word="work">work</span> <span word="may">may</span> <span word="have">have</span> <span word="found">found</span> <span word="out">out</span> <span word="the">the</span> <span word="reason">reason</span> <span word="why">why</span> <span word="a">a</span> <span word="near">near</span>-<span word="starvation">starvation</span> <span word="diet">diet</span> <span word="prolongs">prolongs</span> <span word="the">the</span> <span word="life">life</span> <span word="of">of</span> <span word="many">many</span> <span word="animals">animals</span>.</p><p> <span word="Ronald">Ronald</span> <span word="Kahn">Kahn</span> <span word="at">at</span> <span word="Harvard">Harvard</span> <span word="Medical">Medical</span> <span word="School">School</span> <span word="in">in</span> <span word="Boston">Boston</span>, <span word="US">US</span>, <span word="and">and</span> <span word="his">his</span> <span word="colleagues">colleagues</span> <span word="have">have</span> <span word="been">been</span> <span word="able">able</span> <span word="to">to</span> <span word="extend">extend</span> <span word="the">the</span> <span word="lifespan">lifespan</span> <span word="of">of</span> <span word="mice">mice</span> <span word="by">by</span> 18 <span word="per">per</span> <span word="cent">cent</span> <span word="by">by</span> <span word="blocking">blocking</span> <span word="the">the</span> <span word="rodents">rodents</span> <span word="increase">increase</span> <span word="of">of</span> <span word="fat">fat</span> <span word="in">in</span> <span word="specific">specific</span> <span word="cells">cells</span>. <span word="This">This</span> <span word="suggests">suggests</span> <span word="that">that</span> <span word="thinnessand">thinnessand</span> <span word="not">not</span> <span word="necessarily">necessarily</span> <span word="dietpromotes">dietpromotes</span> <span word="long">long</span> <span word="life">life</span> <span word="in">in</span> <span word="calorie">calorie</span> <span word="restricted">restricted</span> <span word="animals">animals</span>.</p><p> <span word="Its">Its</span> <span word="very">very</span> <span word="cool">cool</span> <span word="work">work</span>, <span word="says">says</span> <span word="aging">aging</span> <span word="researcher">researcher</span> <span word="Cynthia">Cynthia</span> <span word="Kenyon">Kenyon</span> <span word="of">of</span> <span word="the">the</span> <span word="University">University</span> <span word="of">of</span> <span word="California">California</span>, <span word="San">San</span> <span word="Francisco">Francisco</span>. <span word="These">These</span> <span word="mice">mice</span> <span word="eat">eat</span> <span word="all">all</span> <span word="they">they</span> <span word="want">want</span>, <span word="lose">lose</span> <span word="weight">weight</span> <span word="and">and</span> <span word="live">live</span> <span word="longer">longer</span>. <span word="Its">Its</span> <span word="like">like</span> <span word="heaven">heaven</span>.</p><p> <span word="Calorie">Calorie</span> <span word="restriction">restriction</span> <span word="dramatically">dramatically</span> <span word="extends">extends</span> <span word="the">the</span> <span word="lifespan">lifespan</span> <span word="of">of</span> <span word="organisms">organisms</span> <span word="as">as</span> <span word="different">different</span> <span word="as">as</span> <span word="worms">worms</span> <span word="and">and</span> <span word="rodents">rodents</span>. <span word="Whether">Whether</span> <span word="this">this</span> <span word="works">works</span> <span word="in">in</span> <span word="humans">humans</span> <span word="is">is</span> <span word="still">still</span> <span word="unknown">unknown</span>, <span word="partly">partly</span> <span word="because">because</span> <span word="few">few</span> <span word="people">people</span> <span word="are">are</span> <span word="willing">willing</span> <span word="to">to</span> <span word="submit">submit</span> <span word="to">to</span> <span word="such">such</span> <span word="a">a</span> <span word="strict">strict</span> <span word="diet">diet</span>.</p><p> <span word="But">But</span> <span word="many">many</span> <span word="researchers">researchers</span> <span word="hope">hope</span> <span word="they">they</span> <span word="will">will</span> <span word="be">be</span> <span word="able">able</span> <span word="to">to</span> <span word="trigger">trigger</span> <span word="the">the</span> <span word="same">same</span> <span word="effect">effect</span> <span word="with">with</span> <span word="a">a</span> <span word="drug">drug</span> <span word="once">once</span> <span word="they">they</span> <span word="understand">understand</span> <span word="how">how</span> <span word="less">less</span> <span word="food">food</span> <span word="leads">leads</span> <span word="to">to</span> <span word="a">a</span> <span word="longer">longer</span> <span word="life">life</span>. <span word="One">One</span> <span word="theory">theory</span> <span word="is">is</span> <span word="that">that</span> <span word="eating">eating</span> <span word="less">less</span> <span word="reduces">reduces</span> <span word="the">the</span> <span word="increase">increase</span> <span word="of">of</span> <span word="harmful">harmful</span> <span word="things">things</span> <span word="that">that</span> <span word="can">can</span> <span word="damage">damage</span> <span word="cells">cells</span>. <span word="But">But</span> <span word="Kahns">Kahns</span> <span word="team">team</span> <span word="wondered">wondered</span> <span word="whether">whether</span> <span word="the">the</span> <span word="animals">animals</span> <span word="simply">simply</span> <span word="benefit">benefit</span> <span word="by">by</span> <span word="becoming">becoming</span> <span word="thin">thin</span>.</p><p> <span word="To">To</span> <span word="find">find</span> <span word="out">out</span>, <span word="they">they</span> <span word="used">used</span> <span word="biology">biology</span> <span word="tricks">tricks</span> <span word="to">to</span> <span word="disrupt">disrupt</span> <span word="the">the</span> <span word="insulin">insulin</span> <span word="receptor">receptor</span> <span word="gene">gene</span> <span word="in">in</span> <span word="lab">lab</span> <span word="micebut">micebut</span> <span word="only">only</span> <span word="in">in</span> <span word="their">their</span> <span word="fat">fat</span> <span word="cells">cells</span>. <span word="Since">Since</span> <span word="insulin">insulin</span> <span word="is">is</span> <span word="needed">needed</span> <span word="to">to</span> <span word="help">help</span> <span word="fat">fat</span> <span word="cells">cells</span> <span word="store">store</span> <span word="fat">fat</span>, <span word="these">these</span> <span word="animals">animals</span> <span word="were">were</span> <span word="protected">protected</span> <span word="against">against</span> <span word="becoming">becoming</span> <span word="fat">fat</span>, <span word="explains">explains</span> <span word="Kahn">Kahn</span>.</p><p> <span word="This">This</span> <span word="slight">slight</span> <span word="genetic">genetic</span> <span word="change">change</span> <span word="in">in</span> <span word="a">a</span> <span word="single">single</span> <span word="tissue">tissue</span> <span word="had">had</span> <span word="dramatic">dramatic</span> <span word="effects">effects</span>. <span word="By">By</span> <span word="three">three</span> <span word="months">months</span> <span word="of">of</span> <span word="age">age</span>, <span word="Kahns">Kahns</span> <span word="modified">modified</span> <span word="mice">mice</span> <span word="had">had</span> <span word="up">up</span> <span word="to">to</span> 70 <span word="per">per</span> <span word="cent">cent</span> <span word="less">less</span> <span word="body">body</span> <span word="fat">fat</span> <span word="than">than</span> <span word="normal">normal</span> <span word="control">control</span> <span word="mice">mice</span>, <span word="despite">despite</span> <span word="the">the</span> <span word="fact">fact</span> <span word="that">that</span> <span word="they">they</span> <span word="ate">ate</span> 55 <span word="per">per</span> <span word="cent">cent</span> <span word="more">more</span> <span word="food">food</span> <span word="per">per</span> <span word="gram">gram</span> <span word="of">of</span> <span word="body">body</span> <span word="weight">weight</span>.</p>
页:
[1]