托福阅读的背景内容涉及人文历史、生命科学和天文地质等等，各个学科的专有词汇让同学们背得头疼。有上知天文下知地理的学霸直接靠自己的背景知识就能做对题目，但是托福阅读出题的本意并不是想考查学生学科知识的丰富程度，而是靠基础词汇（高四六托福核心）和逻辑来读懂文章想要表达的内容。其中，与逻辑（包括因果、比较、条件、转折让步等）相关的句子往往是文章的重点，而且比较好拿分，各个水平阶段的学生都应该掌握。

结合多位同学的错题情况，本文分析下应如何结合比较逻辑来解题：

首先，注意原文/题目/选项中出现的比较逻辑词：

表相同"

1.same、similar、equal、alike、identical（可靠identicaltwins同卵双胞胎"来背诵这个单词）

2.as...as、justas

3.前缀homo-

表不同"

1.比较级-er...than、高级themost/-est

2.ratherthan(而不是)

3.whereas、while、although/but、unlike、notas…as

其次，定位好后将原句与选项进行同义转换

表相同"的情况：

TPO48R2DeterminingDinosaurDiet

Animalssuchashousecatsanddogshavelarge,stabbingcanineteethatthefrontofthemouthandsmaller,equallysharpteethfartherbackintheirjaws.Manyoftheseanimalsarealsoarmedwithsharpclaws.Theadvantageofteethandclawsaspredatorytoolsisobvious.Nowconsideranimalslikecows,horses,rabbits,andmice.Theseanimalshaveflatteethatthebackofthejawthatareanalogoustoandhavethesamefunctionasgrindstones.Unlikethemeat-slicingandstabbingteethofcarnivores,theteethoftheseanimalsgrindandshredplantmaterialbeforedigestion.

2.Accordingtoparagraph2,whichofthefollowingistrueoftheteethofcarnivores?

A.Carnivores’teethforgrindingandshreddingarelocatedinthefrontoftheirjaws

B.Carnivoreteetharedesignedtobreakdownfoodthoroughlybeforedigestion

C.Carnivoreshaveteethatthebackoftheirjawsthatareassharpastheirfrontteeth

D.Carnivoreshavebothsharpteethforslicingmeatandflatteethforgrindingmeat

分析：原文说某些动物嘴里前面大的牙齿和后面小的牙齿一样锋利（equallysharp），同义替换C选项…back…assharpas…front…"。

TPO41R3TradeAndEarlyStateFormation

Inthe1970s,anumberofarchaeologistsgavetradeaprimaryroleintheriseofancientstates.BritisharchaeologistColinRenfrewattributedthedramaticfloweringoftheMinoancivilizationonCreteandthroughtheAegeantointensifiedtradingcontactsandtotheimpactofoliveandvinecultivationonlocalcommunities.Asagriculturaleconomiesbecamemorediversifiedandlocalfoodsuppliescouldbepurchasedbothlocallyandoverlongerdistances,afar-reachingeconomicinterdependenceresulted.Eventually,thisledtoredistributionsystemsforluxuriesandbasiccommodities,systemsthatwereorganizedandcontrolledbyMinoanrulersfromtheirpalaces.Astimewenton,theself-sufficiencyofcommunitieswasreplacedbymutualdependence.Interestinlong--distancetradebroughtaboutsomeculturalhomogeneityfromtradeandgiftexchange,andperhapsevenledtopiracy.Thus,intensifiedtradeandinteraction,andthefloweringofspecialistcrafts,inacomplexprocessofpositivefeedback,ledtomuchmorecomplexsocietiesbasedonpalaces,whichweretheeconomichubsofanewMinoancivilization.

5.Accordingtoparagraph2,Renfrewbelievedthatoneeffectoflong-distancetradeintheAegeanwas

A.agreaterefforttocontrolpiracy

B.greaterculturalsimilaritythroughouttheregion

C.adeclineinlocaloliveproduction

D.adeclineintheuseofluxuriesforgiftexchanges

分析：用effectoflong-distancetrade"定位到原句后，culturalhomo-"同义转换成选项B里的culturalsimilarity"（都表文化相同）。

表不同"的情况：

TPO44R3Seagrasses

Seagrassbedsundertheinfluenceofstrongcurrentstendtohavemanyofthelighterparticles,includingseagrassdebris,movedout,whereasbedsinweakcurrentareasaccumulatelighterdetritalmaterial.

Question:Whichofthesentencesbelowbestexpressestheessentialinformationinthehighlightedsentenceinthepassage?Incorrectchoiceschangethemeaninginimportantwaysorleaveoutessentialinformation

A.Lightparticlesanddebriscollectinsomeseagrassbeds,butarewashedoutofthoseaffectedbystrongcurrents.

B.Seagrassbedsundertheinfluenceofstrongcurrentstendtoaccumulatemanyofthelighterparticlesfromotherbeds.

C.Thestrengthofthecurrentsdetermineshowquicklyaccumulatedseagrassdebrisismovedoutofthebeds.

D.Seagrassdebrisandotherlightparticlesareoftenmovedfromareasofstrongcurrentstoareasofweakcurrents.

分析：对于部分词汇不够完善的同学来说，这个原句有一定难度；但原句出现whereas，同学们要理解成拿strongcurrents"和weakcurrents"进行比较。只有选项A用虽然但是"来表达出比较的意思，所以即使在原句没有完全读懂的基础上，也应该选A。

长难句：Immediatelyadjacenttothetimberline,thetundraconsistsofafairlycompletecoveroflow-lyingshrubs,herbs,andgrasses,whilehigherupthenumberanddiversityofspeciesdecreaseuntilthereismuchbaregroundwithoccasionalmossesandlichensandsomeprostratecushionplants.

分析：这个句子难点在于和植物相关的专业词汇非常多，逐字逐句翻译非常困难而且浪费时间。此句出现while，而且后接在更高的地方（higherup），物种的数量和多样性会下降"，所以应该根据对比逻辑合理猜测：在海拔低的地方，植物的多样性和数量都会上升。特别是在题目没有对此句进行提问的情况下，靠逻辑读句更能加快读句速度。