1大学英语四六级考试阅读提高练习题及答案(38)
<p> <span word="Sugar">Sugar</span> <span word="is">is</span> <span word="so">so</span> <span word="much">much</span> <span word="a">a</span> <span word="part">part</span> <span word="of">of</span> <span word="our">our</span> <span word="modern">modern</span> <span word="life">life</span> <span word="that">that</span> <span word="we">we</span> <span word="only">only</span> <span word="really">really</span> <span word="think">think</span> <span word="about">about</span> <span word="it">it</span> <span word="when">when</span>, <span word="for">for</span> <span word="some">some</span> ___1___ , <span word="we">we</span> <span word="cannot">cannot</span> <span word="obtain">obtain</span> <span word="it">it</span>. <span word="It">It</span> <span word="has">has</span> <span word="been">been</span> <span word="known">known</span> <span word="to">to</span> <span word="man">man</span> <span word="for">for</span> <span word="at">at</span> <span word="least">least</span> 3,000 <span word="years">years</span>, <span word="but">but</span> <span word="has">has</span> ___2___ <span word="into">into</span> <span word="common">common</span> <span word="use">use</span> <span word="only">only</span> <span word="in">in</span> ___3___<span word="times">times</span>. <span word="Until">Until</span> <span word="quite">quite</span> <span word="recently">recently</span> <span word="it">it</span> <span word="was">was</span> <span word="considered">considered</span> <span word="as">as</span> <span word="a">a</span> <span word="medicine">medicine</span> <span word="and">and</span> <span word="as">as</span> <span word="a">a</span> <span word="luxury">luxury</span> <span word="for">for</span> <span word="the">the</span> <span word="very">very</span> <span word="rich">rich</span> <span word="only">only</span>.</p><p> <span word="Sugar">Sugar</span> <span word="is">is</span>, <span word="then">then</span>, ___4 ___<span word="to">to</span> <span word="our">our</span> <span word="civilization">civilization</span>. <span word="But">But</span> <span word="what">what</span>___5___ <span word="is">is</span> <span word="it">it</span>? <span word="Of">Of</span> <span word="course">course</span>, <span word="most">most</span> <span word="of">of</span> <span word="us">us</span> <span word="recognize">recognize</span> <span word="sugar">sugar</span> <span word="immediately">immediately</span> <span word="as">as</span> <span word="the">the</span> <span word="sweet">sweet</span> <span word="material">material</span> <span word="which">which</span> <span word="we">we</span> <span word="put">put</span> <span word="in">in</span> <span word="coffee">coffee</span> <span word="or">or</span> <span word="cakes">cakes</span>. <span word="This">This</span> <span word="common">common</span> <span word="form">form</span> <span word="of">of</span> <span word="sugar">sugar</span> <span word="is">is</span> <span word="derived">derived</span> <span word="from">from</span> <span word="two">two</span> <span word="plants">plants</span>: <span word="the">the</span> <span word="sugar">sugar</span> <span word="cane">cane</span> <span word="and">and</span> <span word="the">the</span> <span word="sugar">sugar</span> <span word="beet">beet</span> . <span word="But">But</span> <span word="there">there</span> <span word="are">are</span> <span word="in">in</span> <span word="fact">fact</span> <span word="many">many</span> <span word="types">types</span> <span word="of">of</span> <span word="sugar">sugar</span>, <span word="and">and</span> <span word="the">the</span> <span word="chemist">chemist</span> <span word="recognizes">recognizes</span> <span word="hundreds">hundreds</span> <span word="of">of</span> <span word="different">different</span> ___6___ , <span word="each">each</span> <span word="coming">coming</span> <span word="from">from</span> <span word="a">a</span> <span word="different">different</span> <span word="source">source</span>.</p><p> <span word="About">About</span> 90% <span word="of">of</span> <span word="the">the</span> <span word="sugar">sugar</span> <span word="is">is</span> <span word="produced">produced</span> <span word="as">as</span> <span word="food">food</span>. <span word="Only">Only</span> 10% <span word="is">is</span> <span word="used">used</span> <span word="in">in</span> <span word="industry">industry</span> <span word="for">for</span> ___7___<span word="other">other</span> <span word="than">than</span> <span word="food">food</span> <span word="production">production</span>. <span word="Yet">Yet</span> <span word="sugar">sugar</span> <span word="has">has</span> <span word="great">great</span> <span word="possibilities">possibilities</span> <span word="for">for</span> <span word="use">use</span> <span word="as">as</span> <span word="the">the</span> <span word="basis">basis</span> <span word="of">of</span> <span word="chemicals">chemicals</span>. <span word="It">It</span> <span word="can">can</span> <span word="even">even</span> <span word="be">be</span> <span word="used">used</span> <span word="for">for</span> <span word="making">making</span> <span word="plastics">plastics</span>. <span word="In">In</span> <span word="the">the</span> <span word="future">future</span> <span word="these">these</span> <span word="potential">potential</span> <span word="uses">uses</span> <span word="will">will</span> <span word="certainly">certainly</span> <span word="be">be</span> <span word="developed">developed</span> <span word="more">more</span> <span word="than">than</span> <span word="in">in</span> <span word="the">the</span> <span word="past">past</span></p><p> <span word="There">There</span> <span word="are">are</span> <span word="many">many</span> <span word="reasons">reasons</span> <span word="why">why</span> <span word="we">we</span> <span word="should">should</span> ___8___<span word="the">the</span> <span word="production">production</span> <span word="of">of</span> <span word="sugar">sugar</span>. <span word="Most">Most</span> <span word="important">important</span> <span word="is">is</span> <span word="that">that</span> <span word="it">it</span> <span word="is">is</span> <span word="one">one</span> <span word="of">of</span> <span word="the">the</span> <span word="most">most</span> <span word="highly">highly</span> <span word="concentrated">concentrated</span> <span word="of">of</span> <span word="energy">energy</span> <span word="foods">foods</span>.</p><p> <span word="Thus">Thus</span> <span word="sugar">sugar</span> <span word="cane">cane</span> <span word="and">and</span> <span word="beet">beet</span> <span word="produce">produce</span> <span word="an">an</span> <span word="average">average</span> <span word="of">of</span> 7,000,000 <span word="calories">calories</span> <span word="per">per</span> <span word="acre">acre</span>. <span word="In">In</span> <span word="this">this</span> <span word="way">way</span> <span word="they">they</span> <span word="have">have</span> <span word="the">the</span> <span word="advantage">advantage</span> <span word="over">over</span> <span word="potatoes">potatoes</span> <span word="which">which</span> <span word="give">give</span> <span word="only">only</span> 4, 000, 000, <span word="while">while</span> <span word="the">the</span>___9___ <span word="for">for</span> <span word="wheat">wheat</span> <span word="and">and</span> <span word="beans">beans</span> <span word="is">is</span> 2 ,000,000 <span word="each">each</span>. <span word="So">So</span> <span word="three">three</span> <span word="acres">acres</span> <span word="of">of</span> <span word="land">land</span> <span word="growing">growing</span> <span word="wheat">wheat</span>, <span word="beans">beans</span> <span word="and">and</span> <span word="potatoes">potatoes</span> <span word="give">give</span> <span word="only">only</span> ___10__<span word="more">more</span> <span word="energy">energy</span> <span word="than">than</span> <span word="one">one</span> <span word="acre">acre</span> <span word="of">of</span> <span word="sugar">sugar</span>.</p>
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