托福阅读练习4Word文档格式.docx
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oftheanswerbecameclear:
theelectronsareproducedinjetsthatareshotoutin
oppositedirectionsfromthecenterofagalaxy.Remarkablynarrowandhighlydirectional,
(20)thejetsmoveoutwardatspeedsclosetothespeedoflight.Whenthejetsstrikethe
highlyrarefiedgasthatpermeatesintergalacticspace,thefast-movingelectronslose
theirhighlydirectionalmotionandformvastcloudsofradio-emittinggas.
Cosmicjetshaverankedamongthehottesttopicsofastronomicalresearchinrecent
yearsasastronomersstrivetounderstandwheretheycomefrom.Whyshouldagalaxy
(25)ejectmatteratsuchtremendousspeedsintwonarrowjets?
Andwhyaresuchjetsnot
seenintheMilkyWay?
1.Theword"
celestial"
inline1couldbestbe
replacedby
(A)visible
(B)astronomical
(C)glowing
(D)scientific
2.Theword"
entities"
inline4isclosestin
meaningto
(A)factors(B)processes
(C)objects(D)puzzles
3.Inthefirstparagraph,theauthordescribes
objectsintheuniverseintermsoftheir
(A)color(B)origin
(C)location(D)shape
4.Whichofthefollowingisthebest
representationofthecloudsofradioemission
describedinthefirstparagraph?
(A)
(B)
(C)
(D)
5.Accordingtothepassage,scientistsdonot
fullyunderstandwhydoubleradiosources
(A)havenoteventuallydisappeared
(B)cannotbeobservedwithatelescope
(C)arebeginningtoslowdown
(D)arenotasbigassomeplanetsandstars
6.Theword"
their"
inline22refersto
(A)speeds
(B)directions
(C)electrons
(D)clouds
7.Accordingtothepassage,whathappenswhen
electronsandgascollideinspace?
(A)Thegasbecomesmorecondensed.
(B)Thegasbecomeslessradiated.
(C)Theelectronsdisperse.
(D)Theelectronsbecomenegativelycharged.
8.Theauthorsuggeststhatastronomersconsider
thestudyofcosmicjetstobe
(A)anobsoletescientificfield
(B)anunprofitableventure
(C)anintriguingchallenge
(D)asubjectivedebate
9.Inwhatlinesdoesthepassagecomparethe
sizeofdoubleradiosourceswiththatofother
galaxies?
(A)Lines4-6(B)Lines12-14
(C)Lines19-20(D)Lines23-24
10.Whereinthepassagedoestheauthormention
atechnologythataidedintheunderstandingof
doubleradiosources?
(A)Lines2(B)Line7
(C)Line17(D)Line21
11.Theparagraphfollowingthepassagemost
likelydiscusses
(A)specificdoubleradiosources
(B)anexplanationofthesynchrotronprocess
(C)possiblereasonsforthepresenceofcosmic
jets
(D)thediscoveryofthefirstdoubleradio
sources
Passage2
Botany,thestudyofplants,occupiesapeculiarpositioninthehistoryofhumanknowledge.
Formanythousandsofyearsitwastheonefieldofawarenessaboutwhichhumanshad
anythingmorethanthevaguestofinsights.ItisimpossibletoknowtodayjustwhatourStone
Ageancestorsknewaboutplants,butfromwhatwecanobserveofpreindustrialsocietiesthat
(5)stillexist,adetailedlearningofplantsandtheirpropertiesmustbeextremelyancient.Thisis
logical.Plantsarethebasisofthefoodpyramidforalllivingthings,evenforotherplants.They
havealwaysbeenenormouslyimportanttothewelfareofpeople,notonlyforfood,butalsofor
clothing,weapons,tools,dyes,medicines,shelter,andagreatmanyotherpurposes.Tribes
livingtodayinthejunglesoftheAmazonrecognizeliterallyhundredsofplantsandknow
(10)manypropertiesofeach.Tothembotany,assuch,hasnonameandisprobablynoteven
recognizedasaspecialbranchof"
knowledge"
atall.
Unfortunately,themoreindustrializedwebecomethefartherawaywemovefromdirect
contactwithplants,andthelessdistinctourknowledgeofbotanygrows.Yeteveryonecomes
unconsciouslyonanamazingamountofbotanicalknowledge,andfewpeoplewillfailto
(15)recognizearose,anapple,oranorchid.WhenourNeolithicancestors,livingintheMiddle
Eastabout10,000yearsago,discoveredthatcertaingrassescouldbeharvestedandtheirseeds
plantedforricheryieldsthenextseason,thefirstgreatstepinanewassociationofplantsand
humanswastaken.Grainswerediscoveredandfromthemflowedthemarvelofagriculture:
cultivatedcrops.Fromthenon,humanswouldincreasinglytaketheirlivingfromthecontrolled
(20)productionofafewplants,ratherthangettingalittlehereandalittletherefrommanyvarieties
thatgrewwild-andtheaccumulatedknowledgeoflensofthousandsofyearsofexperience
andintimacywithplantsinthewildwouldbegintofadeaway.
12.Whichofthefollowingassumptionsaboutearly
humansisexpressedinthepassage?
(A)Theyprobablyhadextensiveknowledgeof
plants.
(B)Theydividedknowledgeintowell-defined
fields.
(C)Theydidnotenjoythestudyofbotany.
(D)Theyplacedgreatimportanceonownership
ofproperty.
13.Theword"
peculiar"
inline1isclosestin
meaningto
(A)clear
(B)large
(C)unusual
(D)important
14.Whatdoesthecomment"
Thisislogical"
in
lines5-6mean?
(A)Thereisnoclearwaytodeterminethe
extentofourancestorsknowledgeofplants.
(B)Itisnotsurprisingthatearlyhumanshada
detailedknowledgeofplants.
(C)Itisreasonabletoassumethatourancestors
behaveverymuchlikepeoplein
preindustrialsocieties.
(D)Humanknowledgeofplantsiswell
organizedandverydetailed.
15.Thephrase"
propertiesofeach"
inline10refers
toeach
(A)tribe
(B)hundred
(C)plant
(D)purpose
16.Accordingtothepassage,whyhasgeneral
knowledgeofbotanydeclined?
(A)Peoplenolongervalueplantsasauseful
resource.
(B)Botanyisnotrecognizedasaspecialbranch
ofscience.
(C)Researchisunabletokeepupwiththe
increasingnumberofplants.
(D)Directcontactwithavariety,ofplantshas
decreased.
17.Inline15,whatistheauthor'
spurposein
mentioning"
arose,anapple,oranorchid"
?
(A)Tomakethepassagemorepoetic
(B)Tociteexamplesofplantsthatareattractive
(C)Togivebotanicalexamplesthatmostreaders
willrecognize
(D)Toillustratethediversityofbotanicallife
18.Accordingtothepassage,whatwasthefirst
greatsteptowardthepracticeofagriculture?
(A)Theinventionofagriculturalimplements
andmachinery
(B)Thedevelopmentofasystemofnamesfor
plants
(C)Thediscoveryofgrassesthatcouldbe
harvestedandreplanted
(D)Thechangingdietsofearlyhumans
19.Theword"
controlled"
inline19isclosestin
(A)abundant
(B)managed
(C)required
(D)advanced
20.Therelationshipbetweenbotanyandagriculture
issimilartotherelationshipbetweenzoology
(thestudyofanimals)
(A)deerhunting
(B)birdwatching
(C)sheepraising
(D)horsebackriding
21.Whereinthepassagedoestheauthordescribe
thebenefitspeoplederivefromplants?
(A)Line1
(B)Lines6-8
(C)Lines10-11
(D)Lines13-15
PASSAGE3
Ifthephysicalbarriersoftheplantarebreached,thenpreformedchemicalsmayinhibitorkilltheintruder,andplanttissuescontainadiversearrayoftoxicorpotentiallytoxicsubstances,suchasresins,tannins,glycosides,andalkaloids,manyofwhicharehighlyeffectivedeterrentstoinsectsthatfeedonplants.ThesuccessoftheColoradobeetleininfestingpotatoes,forexample,seemstobecorrelatedwithitshightolerancetoalkaloidsthatnormallyrepelpotentialpests.Otherpossiblechemicaldefenses,whilenotdirectlytoxictotheparasite,mayinhibitsomeessentialstepintheestablishmentofaparasiticrelationship.
22.WhichofthefollowingsubstancesdoestheauthormentionasNOTnecessarilybeingtoxictotheColoradobeetle?
(A)Resins
(B)Tannins
(C)Glycosides
(D)Alkaloids
PASSAGE4
Eachpueblorepresentedanastonishingamountofwell-organizedlabor.Usingonlystoneandwoodtools,andwithoutbenefitofwheelsordraftanimals,thebuildersquarriedtonupontonofsandstonefromthecanyonwalls,cutitintosmallblocks,hauledtheblockstotheconstructionsite,andfittedthemtogetherwithmudmortar.Roofbeamsofpineorfirhadtobecarriedfromloggingareasinthemountainforestsmanykilometersaway.Then,toconnectthepueblosandtogiveaccesstothesurroundingtableland,thearchitectslaidoutasystemofpublicroadswithstonestaircasesforascendingcli