TOEFL阅读理解真题整合

TOEFL阅读理解真题整合托福阅读真题1Glaciersarelargemassesoficeonlandthatshowevidenceofpastorpresentmovement.Theygrowbythegradualtransformationofsnowintoglacierice.Afreshsnowfallisafluffymassoflooselypackedsnowflakes,smalldelicateicecrystalsgrownintheatmosphere.Asthesnowagesonthegroundforweeksormonths,thecrystalsshrinkandbecomemorecompact,andthewholemassbecomessqueezedtogetherintoamoredenseform,granularsnow.Asnewsnowfallsandburiestheoldersnow,thelayersofgranularsnowfurthercompacttoformfirm,amuchdenserkindofsnow,usuallyayearormoreold,whichhaslittleporespace.Furtherburialandslowcementation—aprocessbywhichcrystalsbecomeboundtogetherinamosaicofintergrownicecrystals—finallyproducesolidglacialice.Inthisprocessofrecrystallization,thegrowthofnewcrystalsattheexpenseofoldones,thepercentageofairisreducedfromabout90percentforsnowflakestolessthan20percentforglacierice.Thewholeprocessmaytakeaslittleasafewyears,butmorelikelytenortwentyyearsorlonger.Thesnowisusuallymanymetersdeepbythetimethelowerlayersareconvertedintoice.IncoldglaciersthoseformedinthecoldestregionsoftheEarth,theentiremassoficeisattemperaturesbelowthemeltingpointandnofreewaterexists.Intemperateglaciers,theiceisatthemeltingpointateverypressurelevelwithintheglacier,andfreewaterispresentassmalldropsoraslargeraccumulationsintunnelswithinorbeneaththeice.Formationofaglacieriscompletewhenicehasaccumulatedtoathickness(andthusweight)sufficienttomakeitmoveslowlyunderpressure,inmuchthesamewaythatsolidrockdeepwithintheEarthcanchangeshapewithoutbreaking.Oncethatpointisreached,theiceflowsdownhill,eitherasatongueoficefillingavalleyorasthickicecapthatflowsoutindirectionsfromthehighestcentralareawherethemostsnowaccumulates.Thetripdownleadstotheeventualmeltingofice.Whichofthefollowingdoesthepassagemainlydiscuss?TheeffectofglaciersonclimateDamagefromglaciersGlacierformationThelocationofglaciersWhichofthefollowingwillcausedensitywithintheglaciertoincrease?IncreasedwaterandaircontentPressurefromtheweightofnewsnowLongperiodsofdarknessandtemperaturevariationsMovementoftheglacierThewordboundinline9isclosestinmeaningtocoveredchosenplannedheldWhichofthefollowingwillbelostisaglacierforms?AirPressureWeightRocksAccordingtothepassage,whichofthefollowingistheLEASTamountoftimenecessaryforglacialicetoform?severalmonthsseveralyearsatleastfiftyyearsacenturyThewordconvertedinline15isclosestinmeaningtochangeddelayedpromoteddissolvedWhatisthepurposeofthematerialinparagraphthree?TodefinetwotypesofglaciersTocontrastglaciericewithnon-glaciericeTopresenttheoriesofglacierformationTodiscussthesimilaritiesbetweenglacialtypesIntemperateglaciers,whereiswaterfound?OnlynearthesurfaceInpoolsofvariousdepthsInathinlayerbelowthefirmIntunnelsTheworditinline21referstoformationicethicknessweightItcanbeinferredfromthelastparagraphthataglaciercanreverttoafluffymassmaintainsthesameshapethroughouttheglacialprocessistoocoldtobethoroughlystudiedcancontributewatertolakes,rivers,oroceans__74CBDABAADBD托福阅读真题2Manyprehistoricpeoplesubsistedashuntersandgatherers.Undoubtedly,gameanimals,includingsomeverylargespecies,providedmajorcomponentsofhumandiets.AnimportantcontroversycenteringonthequestionofhumaneffectsonprehistoricwildlifeconcernsthesuddendisappearanceofsomanyspeciesoflargeanimalsatorneartheendofthePleistoceneepoch.Mostpaleontologistssuspectthatabruptchangesinclimateledtothemassextinctions.Others,however,haveconcludedthatprehistoricpeopledrovemanyofthosespeciestoextinctionthroughoverhunting.IntheirPleistoceneoverkillhypothesis,theycitewhatseemstobearemarkablecoincidencebetweenthearrivalofprehistoricpeoplesinNorthandSouthAmericaandthetimeduringwhichmammoths,giantgroundsloths,thegiantbison,andnumerousotherlargemammalsbecameextinct.Perhapsthehumanspecieswasdrivingotherstoextinctionlongbeforethedawnofhistory.Hunter-gatherersmayhavecontributedtoPleistoceneextinctionsinmoreindirectways.Besidesoverhunting,atleastthreeotherkindsofeffectshavebeensuggested:directcompetition,imbalancesbetweencompetingspeciesofgameanimals,andearlyagriculturalpractices.Directcompetitionmayhavebroughtaboutthedemiseoflargecarnivoressuchasthesaber-toothedcats.TheseanimalssimplymayhavebeenunabletocompetewiththeincreasinglysophisticatedhuntingskillsofPleistocenepeople.Humanhunterscouldhavecausedimbalancesamonggameanimals,leadingtotheextinctionsofspecieslessabletocompete.Whenotherpredatorssuchasthegraywolfpreyuponlargemammals,theygenerallytakehighproportionsofeachyear'scropofyoung.Somehumanhunters,incontrast,tendtotakethevariousage-groupsoflargeanimalsinproportiontotheiractualoccurrence.Ifsuchhuntersfirstcompetedwiththelargerpredatorsandthenreplacedthem,theymayhaveallowedmoreyoungtosurviveeachyear,graduallyincreasingthepopulationsoffavoredspecies.Asthesepopulationsexpanded,theyinturnmayhavecompetedwithothergamespeciesforthesameenvironmentalniche,forcingthelesshuntedspeciesintoextinction.Thistheory,suggeststhathumanhuntersplayedanindirectroleinPleistoceneextinctionsbyhuntingonespeciesmorethananother.Whatdoesthepassagemainlydiscuss?TheeffectsofhumanactivitiesonprehistoricwildlifeTheoriginsofthehunter-gathererwayoflifeThedietsoflargeanimalsofthePleistoceneepochThechangeinclimateattheendofthePleistoceneepochThewordUndoubtedlyinline1isclosestinmeaningtooccasionallyunexpectedlypreviouslycertainlyThewordcomponentsinline2isclosestinmeaningtopartsproblemschangesvarietiesWhichofthefollowingismentionedassupportingthePleistoceneoverkillhypothesis?Manyoftheanimalsthatbecameextinctwerequitelarge.Humansmigratedintocertainregionsaroundthetimethatmajorextinctionsoccurred.Thereisevidencethatnewspecieswerearrivinginareasinhabitedbyhumans.Humansbegantokeepandcareforcertainanimals.ThewordBesidesinline14isclosestinmeaningtocausedbywhereasinadditiontoinfavorofTheauthormentionssaber-toothedcatsinline17asanexampleofacarnivorethatbecameextinctbeforethePleistoceneepochwasunusuallylargeforitstimewasnotabletocompetewithhumanscausedtheextinctionofseveralspeciesThewordtheyinline22referstohumanhuntersgameanimalsotherpredatorslargemammalsAccordingtothepassage,whatisonedifferencebetweenthehuntingdonebysomehumansandthehuntingdonebygraywolves?Somehumanshuntmorefrequentlythangraywolves.Graywolveshuntinlargergroupsthansomehumans.Somehumanscanhuntlargeranimalsthangraywolvescanhunt.Somehumanspreyonanimalsofallages,butgraywolvesconcentratetheireffortsonyounganimals.Thewordfavoredinline26isclosestinmeaningtolargeescapingpreferredlocalAccordingtothepassage,theimbalancesdiscussedinparagraph3mayhaveresultedfromtheeffectofclimatechangesonlargegameanimalslargeanimalsmovingintoanewenvironmenthumanshuntingsomespeciesmorethanothersolderanimalsnotbeingabletocompetewithyoungeranimals__75ADABCCCDCC托福阅读真题3UndertheEarth'stopsoil,atvariouslevels,sometimesunderalayerofrock,therearedepositsofclay.Lookatcutswherehighwayshavebeenbuilttoseeexposedclaybeds;orlookataconstructionsite,wherepocketsofclaymaybeexposed.Riversalsorevealclayalongtheirbanks,anderosiononahillsidemaymakeclayeasilyaccessible.Whatisclaymadeof?TheEarth'ssurfaceisbasicallyrock,anditisthisrockthatgraduallydecomposesintoclay.Rain,streams,alternatingfreezingandthawing,rootsoftreesandplantsforcingtheirwayintocracks,earthquakes,volcanicaction,andglaciers—alloftheseforcesslowlybreakdowntheEarth'sexposedrockycrustintosmallerandsmallerpiecesthateventuallybecomeclay.Rocksarecomposedofelementsandcompoundsofelements.Feldspar,whichisthemostabundantmineralontheEarth'ssurface,isbasicallymadeupoftheoxidessilicaandaluminacombinedwithalkalislikepotassiumandsomeso-calledimpuritiessuchasiron.Feldsparisanessentialcomponentofgraniterocks,andassuchitisthebasisofclay.Whenitiswet,claycanbeeasilyshapedtomakeavarietyofusefulobjects,whichcanthenbefiredtovaryingdegreesofhardnessandcoveredwithimpermeabledecorativecoatingsofglasslikematerialcalledglaze.Justasvolcanicaction,withitsintenseheat,fusestheelementsincertainrocksintoaglasslikerockcalledobsidian,socanweapplyheattoearthenmaterialsandchangethemintoahard,densematerial.Differentclaysneeddifferentheatlevelstofuse,andsome,thelow-fireclays,neverbecomenonporousandwatertightlikehighlyfiredstoneware.Eachclaycanstandonlyacertainamountofheatwithoutlosingitsshapethroughsaggingormelting.Variationsofclaycompositionandthetemperaturesatwhichtheyarefiredaccountforthedifferencesintextureandappearancebetweenachinateacupandanearthenwareflowerpot.Theauthor'smainpointinparagraph1isthatclaydepositsconceallayersofrockcanbefoundinvariousplacesareusuallysmallmustberemovedfromconstructionsitesItcanbeinferredfromthepassagethatclayisLEASTlikelytobeplentifulinwhichofthefollowingareas?indesertsanddunesinforestsonhillsidesnearriversThewordaccessibleinline4is