师大2004年英语Ⅱ.ReadingComprehension(25points)1Imagineeatingeverythingdeliciousyouwantwithnoneofthefat.Thatwouldbegreat,wouldn’tit?New“fakefat”productsappearedonstoreshelvesintheUnitedStatesrecently,butnoteveryoneishappyaboutit.Makersoftheproducts,whichcontainacompoundcalledolestra,sayfoodmanufacturerscannoweliminatefatfromcertainfoods,Critics,however,saythatthenewcompoundcanrobthebodyofessentialvitaminsandnutrientsandcanalsocauseunpleasantsideeffectsinsomepeople.Soitisuptoconsumerstodecidewhetherthenewfat-freeproductstastegoodenoughtokeepeating.Chemistsdiscoveredolestrainthelate1960s,whentheyweresearchingforafatthatcouldbedigestedbyinfantsmoreeasily.Insteadoffindingthedesiredfat,theresearcherscreatedafatthatcan’tbedigestedatall.Normally,specialchemicalsintheintestines“grab”moleculesofregularfatandbreakthemdownsotheycanbeusedbythebody.Amoleculeofregularfatismadeupofthreemoleculesofsubstancescalledfattyacids.ThefattyacidsareabsorbedbytheintestinesandbringwiththemtheessentialvitaminsA,D,EandK.Whenfatmoleculesarepresentintheintestineswithanyofthosevitamins,thevitaminsattachtothemoleculesandarecarriedintothebloodstream.Olestra,whichismadefromsixtoeightmoleculesoffattyacids,istoolargefortheintestinestoabsorb.Itjustslidesthroughtheintestineswithoutbeingbrokendown.Manufacturerssayit’sthatabilitytoslideunchangedthroughtheintestinesthatmakesolestrasovaluableasafatsubstitute.Itprovidesconsumerswiththetasteofregularfatwithoutanybadeffectsonthebody.ButcriticssayolestracanpreventvitaminsA,D,E,andKfrombeingabsorbed.Itcanalsopreventtheabsorptionofcarotenoids,compoundsthatmayreducetheriskofcancer,heartdisease,etc.ManufacturersareaddingvitaminsA,D,EandKaswellascarotenoidstotheirproductsnow.Evenso,somenutritionistsarestillconcernedthatpeoplemighteatunlimitedamountsoffoodmadewiththefatsubstitutewithoutworryingabouthowmanycaloriestheyareconsuming.21.Welearnfromthepassagethatolestraisasubstancethat_____________.A.containsplentyofnutrientsB.rendersfoodscalorie-freewhileretainingtheirvitaminsC.makesfoodseasilydigestibleD.makesfoodsfat-freewhilekeepingthemdelicious22.Theresultofthesearchforaneasilydigestiblefatturnedouttobe_____________.A.commerciallyuselessB.justasanticipatedC.somewhatcontroversialD.quiteunexpected23.Olestraisdifferentfromordinaryfatsinthat_____________.A.itpassesthroughtheintestineswithoutbeingabsorbedB.itfacilitatestheabsorptionofvitaminsbythebodyC.ithelpsreducetheincidenceofheartdiseaseD.itpreventsexcessiveintakeofvitamins24.Whatisapossibleeffectofolestraaccordingtosomecritics?A.Itmayimpairthedigestivesystem.B.Itmayaffecttheoverallfatintake.C.Itmayincreasetheriskofcancer.D.Itmayspoiltheconsumers’appetite.25.Whyarenutritionistsconcernedaboutaddingvitaminstoolestra?A.Itmayleadtotheover-consumptionofvitamins.B.Peoplemaybeinducedtoeatmorethanisnecessary.C.Thefunctionoftheintestinesmaybeweakened.D.Itmaytriggeranewwaveoffakefoodproduction.2Althoughrarelyseen,bats,ascomparedtoothermammals,arequitecommon.Batsranksecondonlytorodentsinnumberanddiversityofspecies.Theirnumbersprobablytotalinthetensofbillions.Batsalsovaryconsiderablyinsize-fromthetinyPhilippinebamboobat,withasix-inchwingspanandweighing1/20thofanouncetothe“flyingfox”withawingspanoffourorfivefeetandweightoftwopounds.Thedietofbatsisvaried.Mosttypeseatinsects,buttheyalsoconsumeblood,pollen,andnectarandfruits.Som...
