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1、Unit2HewKindsofFoodPart1Teacher:Hi,everybody…how'sitgoing?...Good.…Haseveryoneturnedintheirhomework?Allrighty,thenlet'sgetstarted.IFyouremember,lastweekwewerediscussingsomeresearchintheareaofgenetics.Today,I'dliketotalkaboutsomethingI'msureyou'veallheardabout-geneticallymodifiedor"GM"food.Ge
2、neticallymodifiedfoodisfood--eitheraplantoranimal--thathasbeenalteredinthelaboratorybyscientists.Thescientiststakesomethingfromoneplantoranimal,andaddittoadifferentplantoranimaltomakeitgrowinadifferentway.Today,we'lllookatsomeofthebenefits,andthepossiblerisksofgeneticallymodifiedfond.Let'sst
3、artwithadiscussionofsomeofthebenefitsofGMfood.Geneticscientistsarereallytryingtomakefoodplantsthatarebetterthannormalplants,tomakeplantsthatarealteredinwaysthatmaketheplantgrowbetterortastebetterorbehealthiertoeatthannormalplants.Onebenefitisthatgeneticallymodifiedplantsmayneedfewerpesticide
4、sthannormalplants.Forexample,thereisatypeofcornthatisbadforinsects--whentheinsectseatthecornplant,theydie.However,thecorndoesn'thurtpeople.Thistypeofcornisbeneficialbecausefarmersusefewerpesticidestogrowthecorn,andsothereislesspollutionintheenvironment.Alsothecornislessexpensivebecausethefar
5、mersdon'thavetospendalotofmoneyonpesticides.So,byusingfewerpesticides,thecornischeaperandtheenvironmentiscleaner.Anotherbenefitofgeneticallymodifiedplantsisthattheymaygrowbetterthannormalplants.Oneexampleisatypeofgeneticallymodifiedstrawberrythatcangrowincoldweather.Thesearebetterthannormals
6、trawberriesbecausefarmerscanplantthestrawberriesearlierinthespringandlaterinthefall,whennormalstrawberriesusuallydie.So,asaresult,farmerscangrowmanymorestrawberriesthantheyusedto.Sothat'sanotherbenefitplantsthatgrowbetter.Finally,athirdbenefitisthatmanygeneticallymodifiedplantsstayfreshlonge
7、raftertheyareharvested.So,forexample,thereisalandoftomatothatstaysfreshinthestoreforabouttwomonths,insteadofoneortwoweeks.Thismeansthatthereismoretimetogetthefoodtothestoresandthatstoreshavemorerimetosellthefood.Lessfoodisthrownawayandwasted.Soit's
