专题训练（三）AAlongtheriverbanksofAmazonandtheOrinocotherelivesabirdthatswimsbeforeitcanfly,flieslikeafatchicken,eatsgreenleaves,hasthestomachofacowandhasclaw(爪)onitswingswhenyoung.Theybuildtheirhomesabout4.6mabovetheriver,animportantfeature(特征)forthesafetyoftheyoung.Itiscalledthehoatzin.Inappearance,thebirdsofbothsexeslookverymuchalikewithbrownonthebackandcreamandredontheunderside.Theheadissmall,withalargesetoffeathersonthetop,brightredeyes,andblueskin.Itsnearestrelativesarethecommonbirds,cuckoos.Itsmoststrikingfeature,though,isonlyfoundintheyoung.Babyhoatzinshaveaclawontheleadingedgeofeachwingandanotherattheendofeachwingtip.Usingthesefourclaws,togetherwiththebeak(喙),theycanclimbaboutinthebushes,lookingverymuchlikeprimitivebirdsmusthavedone.Whentheyounghoatzinshavelearnedtofly,theylosetheirclaws.DuringthedriermonthsbetweenDecemberandMarchhoatzinsflyabouttheforestingroupsof20to30birds,butinApril,whentherainyseasonbegins,theycollecttogetherinsmallerlivingunitsoftwotosevenbirdsforproducingpurposes.（）1.Whatisthetextmainlyabout?A.Hoatzinsindryandrainyseason.B.TherelativesandenemiesofhoatzinsC.PrimitivebirdsandhoatzinsoftheAmazon.D.Theappearanceandlivinghabitsofhoatzins（）2.Younghoatzinsaredifferentfromtheirparentsinthat______.A.theylooklikeyoungcuckoosB.theyhaveclawsonthewingsC.theyeatalotlikeacowD.theyliveonriverbanks（）3.Whatcanweinferaboutprimitivebirdsfromthetext?A.Theyhadclawstohelpthemclimb.B.TheycouldflylongdistancesC.TheyhadfourwingslikehoatzinsD.Theyhadaheadwithlongfeathersonthetop（）4.Whydohoatzinscollecttogetherinsmallergroupswhentherainyseasoncomes?A.Tofindmorefood.B.ToprotectthemselvesbetterC.TokeepthemselveswarmD.Toproducetheiryoung.BThe2012LondonOlympicshadenoughproblemstoworryabout.Butonemorehasjustbeenadded–acommunicationsblackoutcausedbysolarstorms.AfteraperiodofcalmwithintheSun,scientistshavedetectedthesignsofafleshcycleofsunspotsthatcouldpeakin2012,justintimeforthearrivaloftheOlympictorchinLondon.NowscientistsbelievethatthispeakcouldresultinvastsolarexplosionsthatcouldthrowbillionsoftonsofchargedmattertowardstheEarth,causingstrongsolarstormsthatcouldjamthetelecommunicationssatellitesandinteractlinkssendingfiveOlympicbroadcastfromLondon.“TheSun’sactivityhasastronginfluenceontheEarth.TheOlympiccouldbeinthemiddleofthenextsolarmaximumwhichcouldaffectthefunctionsofcommunicationssatellites,”saidProfessorRichardHarrison,headofspacephysicsattheRutherfordAppletonLaboratoryinOxfordshire.Atthepeakofthecycle,violentoutburstscalledcoronalmassejections(日冕物质抛射)occurintheSun’satmosphere,throwingoutgreatquantitiesofelectrically-chargedmatter.”Acoronalmassejectioncancarryabilliontonsofsolarmaterialintospaceatoveramillionkilometersperhour.Sucheventscanexposeastronautstoadeadlyamount,candisablesatellites,causepowerfailuresonEarthanddisturbcommunications,”ProfessorHarrisonadded.Theriskisgreatestduringasolarmaximumwhenthereisthegreatestnumberofsunspots.NextweekinAmerica,NASAisscheduledtolaunchasatelliteformonitoringsolaractivitycalledtheSolarDynamicsObservatory(SDO),whichwilltakeimagesoftheSunthat10timeclearerthanthemostadvancedtelevisionsavailable.TheRutherfordAppletonLaboratoryhelpedtomakethehigh–techcamerasthatwillcaptureimagesofthesolarflares(太阳耀斑)andexplosionsastheyoccur.ProfessorHarrisonHoldaway,thelab’sdirectorsaidthattheSDOshouldbeabletopr...
