托福预测向来是每个考生考前必看的，因为托福预测还是有一定的效果的，那么今天就和出国留学网的小编一起来看看2020年1月12日托福阅读考试预测。

ModelsofEggDevelopment

1Severaldifferenttheorieshavebeenputforwardtoexplainhowthehard-shelledeggsofland-dwellingreptiles（e.g.lizards）evolvedfromthesofteggsthatamphibians（e.g.frogsandtoads）layinwater.TheRomermodelofeggdevelopmentisnamedafterthelateAlfredRomer，apaleontologistwhoalsobecamedirectoroftheHarvardUniversityMuseumofComparativeZoology.Hisspecialtywasearlyreptilesbecause，hefelt，theywerethekeytounderstandingthegreatreptilediversificationseenintheLatePaleozoicandMesozoicEras（around230millionyearsago）.Romer＇shypothesiswasthatsomeaquaticamphibiansthatis，amphibianslivinginwatercalledanthracosaursbegantolaytheireggsonlandataboutthetimethattheywereevolvingreptile-likeskeletalfeatures.Indeed，someoftheseearlyamphibiansandearliestreptilesaresosimilarintheirskeletonsthattheexacttransitionpointfromonetotheotherisstilldifficulttodetermine.Eventually，though，thetransitionwasmade，buttheseearlyreptilesremainedaquatic.Theadvantageforlayingeggsonlandwasprimarilytoavoidtheaquaticlarval（pre-adult）stageduringwhichimmatureamphibiansliveexclusivelyinwaterwithitsinherentriskofpredatorsanddryingofponds.However，thelandhasitsownsetofdangers，notleastofwhichisthedryingeffectoftheatmosphere.Tocopewiththeseproblems，aseriesofprotectivemembranesdevelopedaroundtheegg，includingahardshell.Onlylaterdidthereptilescompletelyabandonanaquaticlifestyle.

2AnotherhypothesiswasproposedbyGermanpaleontologistRolfKohring，whosespecialtyisfossileggs.InKohring＇smodel，amphibiansduringtheMississippianepoch（360-320millionyearsago）spreadintonutrient-poororcoolerwater.Becauseoftheharsherconditions，eggswereproducedwithlargeryolks，thatis，morenutrientsfortheembryo.Withlargeryolks，theeggswerebigger，andfewerofthemcouldbeproducedbythefemalehundredsratherthanthousands.■Tokeepthelargereggintact，oneormoremembranesweredeveloped，includingonethatsurroundedandprotectedtheegg.■Thisoutermembraneprovidedaplacetosafelystorecalciumions，whicharepoisonous.■Accumulatingthecalciuminahardshellthenmadeitpossiblefortheeggtobelaidonland（itwaspre-adaptedtobelaidthere.）■

3Oneothermodelweshouldconsideristheanti-predatorhypothesisproposedbyGaryandMaryPackardtoexplaintheevolutionofthehard-shelledegg.Theirmodelwasnotconcernedwiththedevelopmentofmembranessurroundingtheeggbutcontinuesthestoryafterthesemembranesappeared.ThePackardsassumethattheearliestreptileslaidleatheryshelledeggsonverywetgroundwheretheycouldabsorbwaterduringtheembryos＇growth.Butlifeonthegroundisnotwithouthazards，basedonstudiesofmodernreptileswithleatheryshelledeggs.Predatoryinsectsandmicrobescanbeamajorcauseofeggmortality.Tocounterthislossofeggs，someoftheearlyreptilesbegansecretingathincalcareous（containingcalciumcarbonate）layer.Thishardlayergavetheembryosabetterchanceofsurvivinguntilhatching.Andthesesurvivorsinturnwouldprobablyleavemoreprogenyonceafewofthemreachedreproductiveage.Intime，athicker，moreresistantshelldeveloped.However，athickereggshellmeantthatlesswatercouldbeabsorbedfortheneedsoftheembryo.Tocompensate，largereggswereproduced，containingagreatdealmorealbumen（eggwhite，awater-solubleprotein）.Atthispoint，therigideggshellhadreachedthebirdegglevelofcomplexity.

4MaryPackardpresentedyetanothermodelwithhercolleagueRogerSeymour.Theynotethatamphibianeggscannevergetverylargebecausethegelatincoatsurroundingthedevelopinglarvaisnotverygoodattransmittingoxygen.Becauseofthisrestriction，wewillneverseefrogeggsthesizeofachicken＇s.ForPackardandSeymour，themajorevolutionarybreakthroughinreptileeggswastheeliminationofthethickgelatincoatandreplacingpartofitwithafibrousmembrane.Thischangeallowedlargereggstobedeveloped.

1.Whichofthesentencesbelowbestexpressestheessentialinformationinthehighlightedsentenceinthe

A.Duringtheperiodthatearlyamphibianschangedintoreptiles，theirskeletonswereexactlythesame.

B.Itisdifficulttoidentifythetimethatearlyamphibianschangedtoreptilesbecausetheirskeletonslookso

muchalike.

C.Theskeletonsofsomeearlyamphibiansandreptilesaresosimilarthatitisdifficulttosaywhichare

amphibiansandwhicharereptiles.

D.Earlyamphibiansandreptileshadthesamekindofskeletonatthesamepointintime.

2.Theword“exclusively”inthepassageisclosestinmeaningto

A.only

B.initially

C.primarily

D.temporarily

3.Accordingtoparagraph1，aquaticamphibianslaidtheireggsonlandinorderto

A.enableyoungamphibianstobenefitfromadryatmosphere

B.ensuretherapiddevelopmentofahardshell

C.enableyoungamphibianstoevolvefeaturesnecessaryforlivingonland

D.protectyoungamphibiansfromthedangersassociatedwithlifeinthewater

4.Theword“Accumulating”inthepassageisclosestinmeaningto

A.Forcing

B.Collecting

C.Distributing

D.Isolating

5.Inparagraph2，whydoestheauthormentiontheinformationaboutcalciumions

A.ToexplainKoherig＇stheorythatamphibianeggsdevelopedatleasttwoprotectiveoutermembranes

B.Toexplainthatthecalciuminahardshellisnotpoisonouswhentheeggislaidonland

C.Toexplainwhy，accordingtoKohring，ahardshellevolved

D.Toexplainwhyonlytheoutermembranestoredcalcium

6.Whichofthefollowingcanbeinferredfromparagraph2abouttherelationshipbetweeneggsandwatertemperature

A.Eggsneededadaptationstosurviveincoldwater.

B.Eggsneededwarmwatertosurvive.

C.Smallereggswereproducedincoldwater.

D.Fewereggswereproducedinwarmwater.

7.Accordingtoparagraph2，allofthefollowingaretrueoftheeggsofamphibiansduringtheMississippian

epochEXCEPT：

A.Theyhadhardshellsmadefromcalciumions.

B.Theyhadlargeryolksthanpreviously.

C.Theyhadprotectivemembranes.

D.Theywereproducedinlargerquantitiesthanpreviously.

8.Theword“counter”inthepassageisclosestinmeaningto

A.escape

B.stop

C.combat

D.delay

9.Accordingtoparagraph3，earlyreptilesbegantodevelopathincalcareouslayeraroundtheeggsothat

A.theembryocouldsurviveattacksfrompredatoryinsectsandmicrobes

B.theembryocouldabsorbsufficientwaterduringitsgrowth

C.thesurvivingembryocouldreachreproductiveage

D.theeggcouldbelaidonland

10.Whichofthefollowingismentionedinparagraph3asadisadvantageofthehardeggshell

A.Itincreasedthehatchingperiod.

B.Itpreventedthedevelopmentoflarge-sizeeggs.

C.Itmadeitmoredifficultfortheembryotoobtainwater.

D.Itmadeitharderfortheembryotosurviveuntilhatching.

11.Theword“breakthrough”inthepassageisclosestinmeaningto

A.effect

B.development

C.requirement

D.goal

12.Whichofthefollowingcanbeinferredfromparagraph4aboutthefibrousmembrane

A.Itservedthesamefunctionasthegelatincoat.

B.Itwaslargerthanthegelatincoat.

C.Itallowedamphibianstoproduceeggsaslargeasthoseofreptiles.

D.Itallowedforbettertransmissionofoxygen.

13.Lookatthefoursquaresthatindicatewherethefollowingsentencecouldbeaddedtothepassage.

Andtherelativelyfewthatwereproducedhadtobeproperlyprotected.

Wherewouldthesentencebestfit？Clickonasquaretoaddthesentencetothepassage.

14.Directions：Anintroductorysentenceforabriefsummaryofthepassageisprovidedbelow.Complete

thesummarybyselectingtheTHREEanswerchoicesthatexpressthemostimportantideasinthepassage.

Someanswerchoicesdonotbelonginthesummarybecausetheyexpressideasthatarenotpresentedinthe

passageorareminorideasinthepassage.Thisquestionisworth2points.

AnswerChoices

A.AlfredRomer＇shypothesiswasthatearlyamphibiansstartedevolvingreptilianskeletalfeatureslong

beforetheystartedlayingeggsonland.

B.AlfredRomertheorizedthatearlyreptilesdevelopedprotectivemembranesaroundtheegginresponseto

thedangerstoyoungamphibiansinwaterandthreatstotheeggonland.

C.InRolfKohring＇sview，earlyreptilesdevelopedprotectivemembranesaroundthelargeeggsthatwere

producedinharshwaterconditions，makingitpossiblefortheeggtobelaidonland.

D.GaryandMaryPackardclaimedthatreptilesdevelopedthehard-shelledegginordertoreducetherateat

whicheggsweredestroyedbypredatoryinsectsandmicrobes.

E.RolfKohringarguedthateggdevelopmentwaspoorduringtheMississippianepochduetonutrient-poor

waters.

F.AccordingtoMaryPackardandRogerSeymour，reptilescouldnotsuccessivelydevelopverylargeeggs

becauseoftheeliminationofthegelatincoat.