gmat og13、og12 rc部分复习资料

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1、TheOfficialGuideforGMAT*Review13thEdition7.4SampleQuestionsEachofthereadingcomprehensionquestionsisbasedonthecontentofapassage.Afterreadingthepassageanswerallquestionspertainingtoitonthebasisofwhatisstatedorimpliedinthepassage.Foreachquestion,selectthebestanswerofthechoicesgi

2、ven.LineBiologistshaveadvancedtwotheoriestoexplainwhyschoolingoffishoccursinsomanyfishspecies.Becauseschoolingisparticularlywidespreadamongspeciesofsmallfish,boththeoriesassumethat(5)schoolingofferstheadvantageofsomeprotectionfrompredators.ProponentsoftheoryAdisputetheassumpt

3、ionthataschoolofthousandsoffishishighlyvisible.Experimentshaveshownthatanyfishcanbeseen,(10)eveninveryclearwater,onlywithinasphereof200metersindiameter.Whenfishareinacompactgroup,thespheresofvisibilityoverlap.Thusthechanceofapredatorfindingtheschoolisonlyslightlygreaterthanth

4、echanceofthepredatorfindingasinglefish(15)swimmingalone.Schoolingisadvantageoustotheindividualfishbecauseapredator'schanceoffindinganyparticularfishswimmingintheschoolismuchsmallerthanitschanceoffindingatleastoneofthesamegroupoffishifthefishweredispersed(20)throughoutanarea.H

5、owever,criticsoftheoryApointoutthatsomefishformschoolseveninareaswherepredatorsareabundantandthuslittlepossibilityofescapingdetectionexists.Theyarguethattheschoolcontinues(25)tobeofvaluetoitsmembersevenafterdetection.TheyadvocatetheoryB,the"confusioneffect,"whichcanbeexplaine

6、dintwodifferentways.Sometimes,proponentsargue,predatorssimplycannotdecidewhichfishtoattack.Thisindecision(30)supposedlyresultsfromapredator'spreferenceforstrikingpreythatisdistinctfromtherestoftheschoolinappearance.Inmanyschoolsthefisharealmostidenticalinappearance,makingitdi

7、fficultforapredatortoselectone.Thesecondexplanationfor(35)the"confusioneffect"hastodowiththesensoryconfusioncausedbyalargenumberofpreymovingaroundthepredator.Evenifthepredatormakesthedecisiontoattackaparticularfish,themovementofotherpreyintheschoolcan(40)bedistracting.Thepre

8、dator'sdifficultycanbecomparedtothatofatennisplayertryingtohitatenni