环球网校职称英语2009年版冲刺班讲义(11)

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1、11Scientistswhostudyinsectshavearealmysteryontheirhands.Allacrossthecountry,honeybeesareleavingtheirhives(蜂巢)andneverreturning.Researcherscallthisphenomenoncolony-collapse(群体瘫痪)disorder.Itisreposedthat25to40percentofthehoneybeesintheUShavevanishedfromtheirhivessincelastfall.Sofar,noonec

2、anexplainwhy.    Colonycollapseisaseriousconcernbecausebeesplayanimportantroleintheproductionofaboutone-thirdofthefoodsweeat.Astheyfeed，honeybeesspreadpollen(花粉)fromflowertoflower.Withoutthisprocess,aplantcan’tproduceseedsorfruits.转自环球网校edu24ol.com转自环球网校edu24ol.com转自环球网校edu24ol.com    N

3、ow,agroupofscientistsandbeekeepershaveteameduptotrytofigureoutwhat’scausingthealarmingcollapseofsomanycolonies.Theyhopetofindoutwhat’scontributingtothedeclineandtopreventbeedisappearanceinthefuture.    Itcouldbethatdiseaseiscausingthedisappearanceofthebees.Toexplorethatpossibility,JayEv

4、ans,aresearcherattheUnitedStatesDepartmentofAgriculture(SDA)BeeResearchLaboratory,examinesbeestakenfromcoloniesthatarecollapsing.“WeknowwhatahealthybeeshouldLookLikeontheinside,andwecanlookforphysicalsignsofdisease.”hesays.Andbeesfromcollapsingcoloniesdon’tlookveryhealthy.“Theirstomachs

5、areworndown,comparedtothestomachsofhealthybees,”Evanssays.Itmaybethataparasite(寄生虫)makingthebees’digestiveorgans.Theirimmune(免疫的)systemsmaynotbeworkingastheyshould.Moreover,theyhavehighlevelsofbacteriainsidetheirbodies.       Anothercauseofcolony-collapsedisordermaybecertainchemicalstha

6、tfarmersapplytokillunwantedinsectsoncrops,saysJerryHayes,chiefbeeinspectorfortheFloridaDepartmentofAgriculture.Somestudies,hesays，suggestthatacertaintypeofinsecticide(杀虫剂)affectsthehoneybee’snewelssystemandmemory.“Itseemslikehoneybeesaregoingoutandgettingconfusedaboutwheretogoandwhattod

7、o,”hesays.    1fitturnsoutthatadiseaseiscontributingtocolonycollapse,bees’genescouldexplainwhysomecolonieshavecollapsedandothershavenot.Inanygroupofbeestherearemanydifferentkindsofgenes.Themoredifferentgenesagrouphas,thehigherthegroup’sgeneticdiversity.Sofarscientistshaven’tdet