SeaOtterdeclining是一个globalissue.当然读托福和雅思，要有个很重要的理念，生态，环境，疾病...都可以是globalissue的。我们在阅读和写作中，要体现出浸透了这个理念，分数容易高起来，毕竟思维上的接近才是根本性的。

新的要求：

托福综合写作是要求概述篇章要义的，对reading部分的精读和速读要求后，便要求概述了。尤其是阅读段，做题的时候，阅读段会在屏幕上出现，所以不允许摘写，要自己概括。练习的时候在读懂速度的基础上，开始做概括。

原文概括

TheseaotterisasmallmammalthatlivesinwatersalongthewesterncoastofNorthAmericafromCaliforniatoAlaska.WhensomeseaotterpopulationsofftheAlaskancoaststartedrapidlydecliningafewyearsago,itcausedmuchconcernbecauseseaottersplayanimportantecologicalroleinthecoastalecosystem.Expertsstartedinvestigatingthecauseofthedeclineandquicklyrealizedthatthereweretwopossibleexplanations:environmentalpollutionorattacksbypredators.Initially,thepollutionhypothesisseemedthemorelikelyofthetwo.

常规的开头，seaotter减少有两种假设，环境污染和被捕杀，作者认同前者。

ThefirstreasonwhypollutionseemedthemorelikelycausewasthattherewereknownsourcesofitalongtheAlaskancoast,suchasoilrigsandothersourcesofindustrialchemicalpollution.Watersamplesfromthearearevealedincreasedlevelsofchemicalsthatcoulddecreasetheotters'resistancetolife-threateninginfectionsandthuscouldindirectlycausetheirdeaths.

首先是Alaskan海岸有已知的各种污染源，比如石油和其他化工原料。

Second,otherseamammalssuchassealsandsealionsalongtheAlaskancoastwerealsodeclining,indicatingthatwhateverhadendangeredtheotterswasaffectingotherseamammalsaswell.Thisfactagainpointedtoenvironmentalpollution,sinceitusuallyaffectstheentireecosystemratherthanasinglespecies.Onlywidelyoccurringpredators,suchastheorca(alargepredatorywhale),couldhavethesameeffect,butorcasprefertohuntmuchlargerprey,suchasotherwhales.

同区域的其他哺乳动物比如海狮等也在减少，说明污染导致整个生态系统变差

Third,scientistsbelievedthatthepollutionhypothesiscouldalsoexplaintheunevenpatternofotterdecline:atsomeAlaskanlocationstheotterpopulationsdeclinedgreatly,whileatotherstheyremainedstable.Someexpertsexplainedtheseobservationsbysuggestingthatoceancurrentsorotherenvironmentalfactorsmayhavecreatedunevenconcentrationsofpollutantsalongthecoast.

第三，科学家们认为，seaotter下降有地区不均衡是因为洋流让污染浓度不均衡。