数学概念的题目ＯＧ202.Gortlandhaslongbeennarrowlyself-sufficientinbothgrainandmeat.However,aspercapitaincomeinGortlandhasrisentowardtheworldaverage,percapitaconsumptionofmeathasalsorisentowardtheworldaverage,andittakesseveralpoundsofgraintoproduceonepoundofmeat.Therefore,sincepercapitaincomecontinuestorise,whereasdomesticgrainproductionwillnotincrease,Gortlandwillsoonhavetoimporteithergrainormeatorboth.Whichofthefollowingisanassumptiononwhichtheargumentdepends?(A)ThetotalacreagedevotedtograinproductioninGortlandwillnotdecreasesubstantially.(B)ThepopulationofGortlandhasremainedrelativelyconstantduringthecountry’syearsofgrowingprosperity.(C)ThepercapitaconsumptionofmeatinGortlandisroughlythesameacrossallincomelevels.(D)InGortland,neithermeatnorgrainissubjecttogovernmentpricecontrols.(E)PeopleinGortlandwhoincreasetheirconsumptionofmeatwillnotradicallydecreasetheirconsumptionofgrain.Consumption分成meatandgrain.此消彼长的关系关于逻辑中数量范围的问题数量的范围是逻辑题常考，特别是MUSTBE问题，混淆答案也常来于此。下面一题是LSAT，先讨论，后再公布答案及解释。（VALARIE说得对，纪念完了，我们要更加努力去学习）Theimportanceoftheozonelayertoterrestrialanimalsisthatitentirelyfiltersoutsomewavelengthsoflightbutletsothersthrough.Holesintheozonelayerandthedangersassociatedwiththeseholesarewelldocumented.However,onedangerthathasnotbeengivensufficientattentionisthattheseholescouldleadtosevereeyedamageforanimalsofmanyspecies.Whichoneofthefollowingismoststronglysupportedbythestatementsabove,iftheyaretrue.A).Allwavelengthsofsunlightthatcancauseeyedamagearefilteredoutbytheozonelayerwhereitisintact.B).Fewspeciesofanimalsliveonapartoftheearth'ssurfacethatisnotthreatenedbyholesintheozonelayerC).SomespeciesofanimalshaveeyesthatwillnotsufferanydamagewhenexposedtounfilteredsunlightD).AsinglewavelengthofsunlightcancauseseveredamagetotheeyesofmostspeciesofanimalsE).Somewavelengthsofsunlightthatcauseeyedamagearemorelikelytoreachtheearth'ssurfacewherethereareholesintheozonelayerthanwheretherearenot,答案都对了，是ETheimportanceoftheozonelayertoterrestrialanimalsisthatitentirelyfilter