每天推送一条四六级听力考试真题的音频。希望对大家的四六级考试有所帮助。

1.

A.High-fiberwheat.

B.Mushroomsthatkeeptheircolor.

C.Highly-productivetomatoes.

D.Ricethatresistspollution.

2.

A.Geneticallymodified.

B.Geneticallyedited.

C.Graft.

D.Genicmutation.

1.Accordingtothenewsreport,whichofthefollowingcropshasnotbeendevelopedyetbasedongeneediting

A.High-fiberwheat.

B.Mushroomsthatkeeptheircolor.

C.Highly-productivetomatoes.

D.Ricethatresistspollution.

2.Accordingtothenewsreport,whattechnologyisitwhenitcomestoaddingDNAfromanotherorganism

A.Geneticallymodified.

B.Geneticallyedited.

C.Graft.

D.Genicmutation.

Foodsbasedonthelatestbiotechnologies（生物技术）willsoonbeavailableingrocerystores（杂货商店）aroundthecountry.Thefirstfoodsfromplantsoranimalsthathavehadtheirgeneticmaterial,orDNA,"edited"areexpectedtoappearonthemarketasearlyasnextyear.Geneticallyeditedfoodusesadifferenttechnologyfrom"geneticallymodified,"orGMO,foods（转基因食物）,whicharealreadyavailableinmanycountriesincludingtheU.S.Geneeditingisneededtoimprovefoodproductioninordertofeedtheworld'sgrowingpopulation.However,governmentsdonotyetknowhowtooversee（监视，监督）thisnewtool.Italsoisunclearwhetherpeoplewillbewillingtobuygene-editedfoods.Researchersareusingthetechnologytomakeseveralnewkindsofcrops.Theyincludehigh-fiber（高纤维的）wheat,mushroomsthatkeeptheircolorandhighly-productive（高产的）tomatoes.Theyalsoaretryingtodevelopcornthatresists（抵抗）dryweatherconditionsandricethatresistspollution.Forhundredsofyears,farmershavegeneticallychangedcropsandanimalsbybreeding（培育）themfordesiredqualities.Thisselective（选择性的）breedingresultsingivingupsomeotherqualities.GMOs,orgeneticallymodifiedorganisms,areplantsandanimalsthathavehadDNAfromotherkindsoforganismsmixedwiththeirowntogivetheneworganismaspecificquality.ScientistsaroundtheworldsayGMOsaresafetoeat.Butthatdoesnotkeepsomepeoplefromnotlikingthem.SomepeoplealsoworrythatGMOswillbringunexpectedresultsastheyinteractwithotherlivingthingsinthenaturalworld.Nowtherearegene-editingtools.ScientistshopethesemethodswillpermitveryexactchangestoplantoranimalDNAwithoutnecessarilyaddingDNAfromanotherorganism.Sofar,researchershaveplacedmostoftheireffortsnotonaddingtoDNAbutoncuttingunwantedpartsfromgenescausingthemto"turnoff."

背景知识：

转基因技术的理论基础来源于进化论衍生来的分子生物学。基因片段[2]的来源可以是提取特定生物体基因组中所需要的目的基因，也可以是人工合成指定序列的DNA片段。DNA片段被转入特定生物中，与其本身的基因组进行重组，再从重组体中进行数代的人工选育，从而获得具有稳定表现特定的遗传性状的个体。该技术可以使重组生物增加人们所期望的新性状，培育出新品种。

基因编辑技术指能够让人类对目标基因进行编辑"，实现对特定DNA片段的敲除、加入等。而CRISPR/Cas9技术自问世以来，就有着其它基因编辑技术无可比拟的优势，技术不断改进后，更被认为能够在活细胞中最有效、最便捷地编辑"任何基因。