雅思阅读考试练习题详细解析

　　雅思阅读考试练习题详细解析

　　A

　　Birdshavemanyuniquedesignfeaturesthatenablethemtoperformsuchamazingfeatsofendurance.

　　Theyareequippedwithlightweight,hollowbones,intricatelydesignedfeathersprovidingboth

　　liftandthrustforrapidflight,navigationsystemssuperiortoanythatmanhasdeveloped,

　　andaningeniousheatconservingdesignthat,amongotherthings,concentratesall

　　bloodcirculationbeneathlayersofwarm,waterproofplumage,

　　leavingthemfittofacelifeintheharshestofclimates.

　　Theirrespiratorysystemshavetoperformefficientlyduringsustainedflightsataltitude,

　　sotheyhaveasystemofextractingoxygenfromtheirlungsthatfarexceedsthatofanyotheranimal.

　　Duringthelaterstagesofthesummerbreedingseason,whenfoodisplentiful

　　theirbodiesareabletoaccumulateconsiderablelayersoffat,

　　inordertoprovidesufficientenergyfortheirlongmigratoryflights.

　　B

　　Thefundamentalreasonthatbirdsmigrateistofindadequate

　　foodduringthewintermonthswhenitisinshortsupply.

　　ThisparticularlyappliestobirdsthatbreedinthetemperateandArcticregionsof

　　theNorthernHemisphere,wherefoodisabundantduringtheshortgrowingseason.

　　Manyspeciescantoleratecoldtemperaturesiffoodisplentiful,

　　butwhenfoodisnotavailabletheymustmigrate.However,intriguingquestionsremain.

　　C

　　Onepuzzlingfactisthatmanybirdsjourneymuchfurtherthanwould

　　benecessaryjusttofindfoodandgoodweather.Nobodyknows,forinstance,

　　whyBritishswallows,whichcouldpresumablysurviveequallywell

　　iftheyspentthewinterinequatorialAfrica,insteadflyseveralthousandsofmilesfurther

　　totheirpreferredwinterhomeinSouthAfricaCapeProvince.Anothermysteryinvolves

　　thehugemigrationsperformedbyarcticternsandmudflat-

　　feedingshorebirdsthatbreedclosetoPolarRegions.Ingeneral,

　　thefurthernorthamigrantspeciesbreeds,thefarthersouthitspendsthewinter.

　　Forarcticternsthisnecessitatesanannualroundtripof25,000miles.

　　Yet,enroutetotheirfinaldestinationinfar-flungsouthernlatitudes,

　　alltheseindividualsoverflyotherareasofseeminglysui

　　tablehabitatspanningtwohemispheres.Whilewemaynotfullyunderstandbirds'

　　reasonsforgoingtoparticularplaces,wecanmarvelattheirfeats.

　　D

　　Oneofthegreatestmysteriesishowyoungbirdsknowhowtofindthetraditional

　　winteringareaswithoutparentalguidance.Veryfewadultsmigratewithjuvenilesintow,

　　andyoungstersmayevenhavelittleornoinklingoftheirparents'appearance.

　　Afamiliarexampleisthatofthecuckoo,whichlaysitseggsinanotherspeciesnestandneverencountersitsyoungagain.

　　Itismindbogglingtoconsiderthat,onceraisedbyitshostspecies,

　　theyoungcuckoomakesitsownwaytoancestralwinteringgroundsinthetropicsbeforereturningsingle-handedtonorthernEuropethenextseasontoseekoutamateamongitsownkind.

　　Theobviousimplicationisthatitinheritsfromitsparentsaninbuiltroutemapanddirection-findingcapability,aswellasamentalimageofwhatanothercuckoolookslike.

　　Yetnobodyhastheslightestideaastohowthisispossible.

　　E

　　Mountingevidencehasconfirmedthatbirdsusethepositionsof

　　thesunandstarstoobtaincompassdirections.Theyseemalsotobeabletodetecttheearth'

　　smagneticfield,probablyduetohavingminutecrystalsofmagnetiteintheregionoftheirbrains.

　　However,truenavigationalsorequiresanawarenessofpositionandtime,especiallywhenlost.

　　Experimentshaveshownthatafterbeingtakenthousandsofmilesoveranunfamiliarlandmass,

　　birdsarestillcapableofreturningrapidlytonestsites.

　　Suchphenomenalpowersarctheproductofcomputinganumberofsophisticatedcues,

　　includinganinbornmapofthenightskyandthepulloftheearth'smagneticfield.

　　Howthebirdsusetheir'instruments’remainsunknown,butonethingisclear:

　　theyseetheworldwithasuperiorsensoryperceptiontoours.

　　Mostsmallbirdsmigrateatnightandtaketheirdirectionfromthepositionofthesettingsun.

　　However,aswellasseeingthesungodown,theyalsoseemtosectheplaneofpolarizedlightcausedbyit,

　　whichcalibratestheircompass.Travelingatnightprovidesotherbenefits.

　　Daytimepredatorsareavoidedandthedangerofdehydrationduetoflyingforlongperiodsinwarm,

　　sunlitskiesisreduced.Furthermore,atnighttheairisgenerally

　　coolandlessturbulentandsoconducivetosustained,stableflight.

　　F

　　Nevertheless,alljourneysinvolveconsiderablerisk,andpartofthe

　　skillinarrivingsafelyissettingoffattherighttime.

　　Thismeansaccurateweatherforecasting,andutilizingfavorablewinds.

　　Birdsareadeptatboth,and,inlaboratorytests,somehavebeenshowntodetecttheminute

　　differenceinbarometricpressurebetweenthefloorandceilingofaroom.

　　Oftenbirdsreacttoweatherchangesbeforethereisanyvisiblesignofthem.Lapwings,

　　whichfeedongrassland,fleewestfromtheNetherlandstotheBritishIsles,

　　FranceandSpainattheonsetofacoldsnap.Whenthegroundsurfacefreezesthebirdscouldstarve.

　　YettheyreturntoHollandaheadofathaw,theirarrivallinkedtoapressurechangepresaginganimprovementintheweather.

　　G

　　InoneinstanceaWelshManxshearwatercarriedtoAmericaandreleasedwasbackinitsburrowonSkokholmIsland,

　　offthePembrokeshirecoast,oneclaybeforealetterannouncingitsrelease!Conversely,

　　eachautumnasmallnumberofNorthAmericanbirdsarcblownacrosstheAtlanticbyfast-movingwesterlytailwinds.NotonlydotheyarrivesafelyinEurope,but,basedonringingevidence,

　　somemakeitbacktoNorthAmericathefollowingspring,afterprobably

　　spendingthewinterwithEuropeanmigrantsinsunnyAfricanclimes.

　　Questions14-20

　　Readingpassage2hassevenparagraphs,A-G

　　Choosethecorrectheadingforeachparagraphfromthelistofheadingsbelow.Write

　　thecorrectnumber,i-x,inboxes14-20onyouranswersheet.

　　Listofheadings

　　i.Thebestmomenttomigrate

　　ii.Theunexplainedrejectionofcloserfeedingground

　　iii.Theinfluenceofweatheronthemigrationroute

　　iv.Physicalcharacteristicsthatallowbirdstomigrate

　　v.Themainreasonwhybirdsmigrate

　　vi.Thebestwinteringgroundsforbirds

　　vii.Researchfindingsonhowbirdsmigrate

　　viii.Successfulmigrationdespitetroubleofwind

　　ix.Contrastbetweenlong-distancemigrationandshort-distancemigration

　　x.Mysteriousmigrationdespitelackofteaching

　　14ParagraphA

　　15ParagraphB

　　16ParagraphC

　　17ParagraphD

　　18ParagraphE

　　19ParagraphF

　　20ParagraphG

　　Questions21-22

　　ChooseTWOletters,A-E.

　　Writethecorrectlettersinboxes21and22onyouranswersheet.

　　WhichTWOofthefollowingstatementsaretrueofbirdmigration?

　　ABirdsoftenflyfurtherthantheyneedto.

　　BBirdstravelinginfamilygroupsaresafe.

　　CBirdsflyingatnightneedlesswater.

　　DBirdshavemuchsharpereye-sightthanhumans.

　　EOnlyshorebirdsareresistanttostrongwinds.

　　Questions23-26

　　CompletethesentencesbelowusingNOMORETHANTWOWORDSfromthe

　　passage.

　　Writeyouranswersinboxes23-26onyouranswersheet.

　　23Itisagreatmysterythatyoungbirdslikecuckooscanfindtheirwinteringgroundswithout________.

　　24Evidenceshowsbirdscantelldirectionslikea________byobservingthesunandthestars.

　　25Oneadvantageforbirdsflyingatnightisthattheycanavoidcontactwith______.

　　26Laboratorytestsshowthatbirdscandetectweatherwithout________signs.

　　文章题目：

　　鸟类迁徙

　　篇章结构

　　体裁论说文

　　题目鸟类迁徙

　　结构A段：鸟类独特的结构特征

　　B段：鸟类迁徙的原因

　　C段：鸟类迁徙到更远目的地的谜团

　　D段：幼鸟迁徙到传统越冬之地的迷思

　　E段：鸟类迁徙途中方向辨别的探究

　　F段：鸟类如何寻找正好的迁徙时间

　　G段：威尔士马恩岛海鸥预测天气变化的例子