托福考试阅读试题及答案.docx

托福考试阅读试题及答案

托福考试阅读试题及答案2017 知识是珍贵宝石的'结晶，文化是宝石放出的光泽。下面是小编为大家搜索整理的托福考试阅读试题及答案2017，希望能给大家带来帮助!更多精彩内容请及时关注我们应届毕业生考试网! TheDevelopmentofSteamPower 【1】Bytheeighteenthcentury,Britainwasexperiencingasevereshortageofenergy.Becauseofthegrowthofpopulation,mostofthegreatforestsofmedievalBritainhadlongagobeenreplacedbyfieldsofgrainandhay.Woodwasinever-shortersupply,yetitremainedtremendouslyimportant.Itservedastheprimarysourceofheatforallhomesandindustriesandasabasicrawmaterial.Processedwood(charcoal)wasthefuelthatwasmixedwithironoreintheblastfurnacetoproducepigiron(rawiron).Theironindustry’sappetiteforwoodwasenormous,andby1740theBritishironindustrywasstagnating.VastforestsenabledRussiatobecom#etheworld’sleadingproducerofiron,muchofwhichwasexportedtoBritain.ButRussia’spotentialforgrowthwaslimitedtoo,andinafewdecadesRussiawouldreachthebarrierofinadequateenergythatwasalreadyholdingEnglandback. 【2】Asthisearlyenergycrisisgrewworse,Britainlookedtowarditsabundantandwidelyscatteredreservesofcoalasanalternativetoitsvanishingwood.CoalwasfirstusedinBritaininthelateMiddleAgesasasourceofheat.By1640mosthomesinLondonwereheatedwithit,anditalsoprovidedheatformakingbeer,glass,soap,andotherproducts.Coalwasnotused,however,toproducemechanicalenergyortopowermachinery.Itwastherethatcoal’spotentialwadenormous. 【3】Asmorecoalwasproduced,minesweredugdeeperanddeeperandwereconstantlyfillingwithwater.Mechanicalpumps,usuallypoweredbyhundredsofhorseswalingincirclesatthesurface,hadtobeinstalledSuchpowerwasexpensiveandbothersome.Inanattempttoovercom#ethesedisadvantages,ThomasSaveryin1698andThomasNewcom#enin1705inventedthefirstprimitivesteamengines.Bothengineswereextremelyinefficient.Bothburnedcoaltoproducesteam,whichwasthenusedtooperateapump.However,bytheearly1770s,manyoftheSaveryenginesandhundredsoftheNewcom#enengineswereoperatingsuccessfully,thoughinefficiently,inEnglishandScottishmines. 【4】Intheearly1760s,agiftedyoungScotnamedJamesWattwasdrawntoacriticalstudyofthesteamengine.Wattwasem