英语四级阅读理解是英语四级考试中的重点部分,而随着时代的发展,英语四级中的阅读题型也在不断更替改变,下面是新东方网考研频道英语四级频道为大家整理的英语四级阅读寒假练习题,希望可以为大家带
树图思维导图提供 2017年大学英语四级阅读寒假练习题(27) 在线思维导图免费制作,点击“编辑”按钮,可对 2017年大学英语四级阅读寒假练习题(27) 进行在线思维导图编辑,本思维导图属于思维导图模板主题,文件编号是:a613dfe96405ca75c86e0f1552ec9ee1
2017年大学英语四级阅读寒假练习题(27)思维导图模板大纲
英语四级阅读理解是英语四级考试中的重点部分,而随着时代的发展,英语四级中的阅读题型也在不断更替改变,下面是新东方网考研频道英语四级频道为大家整理的英语四级阅读寒假练习题,希望可以为大家带来帮助。
Designingalenscanbecomparedtoplayingchess.Inchessaplayertriestotraphisopponent'skinginaseriesofmoves.Increatingalensalensdesignerattemptsto“trap”lightbyforcingalltheraysarisingfromasinglepointinthesubjecttofocusonasinglepointintheimage,asaconsequenceoftheirpassingthroughaseriesoftransparent(透明的)elementswithpreciselycurvedsurfaces.Sinceinbothcasestheultimategoalandthemeansbywhichitcanbeattainedareknown,oneistemptedtothinktherewillbeasinglebestdecisionatanypointalongtheway.Thenumberofpossibleconsequencesflowingfromanyonedecisionissolarge,however,astobevirtually,ifnotactually,infinite.Thereforeinlensdesign,asinchess,perfectsolutionstoaproblemarebeyondreach.Althoughthisarticlewillbeconcernedonlywiththedesignofphotographiclenses,thesameprinciplesapplytoalllenses.
Thelensdesignerhasoneenormousadvantageoverthechessplayer:thedesignerisfreetocallonanyavailablesourceofhelptoguidehimthroughthestaggeringnumberofpossibilities.Mostofthathelponcecamefrommathematicsandphysics,butrecentlycomputertechnology,informationtheory,chemistry,industrialengineeringandpsychophysicshaveallcontributedtomakingthelensdesigner'sjobimmeasurablymoreproductive.Someofthelensesonthemarkettodaywereinconceivableadecadeago.Otherswhosedesignisasmuchasacenturyoldcannowbemassproducedatlowcost.Withthedevelopmentofautomaticproductionmethods,lensesaremadebythemillions,bothoutofglassandoutofplastics.Today'slensesarebetterthanthebestlensesusedbythegreatphotographersofthepast.Moreover,theirpricemaylower,inspiteofthefactthat19thcenturycraftsmenworkedforonlyafewdollarsaweekandtoday'slensesaremorecomplex.Thelensdesignercannotfailtobegratefulforthescienceandtechnologythathavemadehisworkeasierandhiscreationsmorewidelyavailable,butheisalsohumbled:itisnolongerpracticalforafinephotographiclenstobedesignedfrombeginningtoendbyasinglehumanmind.
A)thefinalgoalandthemeansbywhichitcanbereachedareknown
B)perfectsolutionstoaproblemcanbefound
C)anyonedecisionatanypointalongthewaytothegoalcanbringnumerouspossibleresults
D)bothAandC
A)totraptheopponent'slenses
B)tofocuslightwithlenses
C)tohandmakelensesatlowcost
D)toreflectlightbymeansofcurvedsurfaces
A)theprinciplesofdesigninglenses
B)techniquesofmakingcontactlenses
C)thedesignofphotographiclenses
D)stylesoflenses
A)Moredelicate.B)Cheaper.C)Numerous.D)Unpopular.
A)havealargesourceofhelptofallbackonB)receivealowsalary
C)arelessrespectablethanthoseofthepastD)arenotdecisiveinthelensdesign
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