全新版大学英语视听阅读4答案.docx

全新版大学英语视听阅读4答案.docx

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全新版大学英语视听阅读4答案

Unit1ThePerfectSwarmUnit2TheRedDevilsUnit3TheOrientExpress

Unit4TheVariedCulturesofChinaUnit5Afghanistan'sHeroicArtists

Unit6Natacha'sAnimalRescueUnit7FirewalkingUnit8LivingintheSlowLane

Unit9AlternativeEnergyUnit10MarsonEarth

Glossary

Unit1

Thisstoryissetinthecentralandwestern.,particularlyinthestatesofTexas,Oklahoma,Kansas,Nebraska,NorthandSouthDakota,andWyomingaswellastheRockyMountains.

Inthe1800s,theRockyMountainlocustbroughtmassivedestructiontoWesternsettlers.Then,theinsectssuddenlydisappearedalmostwithoutatrace.Nowscientistshopetofindareasonforthelocust'sextinction.WhatcausedtheRockyMountainlocusttodisappearWherewillthescientistsfindtheanswers

I.Locusts!

Readtheparagraph.Thenmatcheachwordwiththecorrectdefinition.

Manyplacesintheworldregularlyexperienceplaguesoflocuststhatcandevastateentirecountries.Locustsmoveinhugeswarms,invadeentireregions,andusuallyconsumeeverythingintheirpath.Oneswarmoflocustscontainingtrillionsofindividualinsectscaneatthousandsoftonsofvegetationaday.Locustsareoneoftheworld'smostdestructiveinsects,buttheythemselvesaresometimesdestroyed.Inthe1800s,forexample,theRockyMountainlocustmysteriouslybecameextinct.

1.plague___E___

2.locust___G___

3.devastate___C___

4.swarm___E___

5.trillion__A

6.vegetation__F

7.extinct___B___

A.1,000,000,000,000

B.nolongerinexistence

C.causeextremedamage

D.anywidespreadcauseofmisery,suffering,ordeath

E.alargegroup,usuallyofinsects

F.theplantcoveringanarea

G.aninsectnotedforflyinginlargegroupsanddestroyingcrops

II.TheRockyMountainLocustMystery.Readtheparagraph.Thencompletethedefinitionswiththebasicformoftheunderlinedwordsorphrases.

Dr.JeffLockwoodisanentomologistwhoisparticularlyinterestedinthedisappearanceoftheRockyMountainlocust.Thespecieswasmysteriouslywipedoutinthelate1800sandtherearen'tmanycluesastowhyithappened.BystudyinglocustspecimensunderamicroscopeandbytakingDNAsamplesfromthedeadlocusts,LockwoodaimstofindoutwhytheRockyMountainlocustsuddenlydisappearedfromEarth.

1.athingorfactthathelpsprovideananswertoaquestion;evidence:

clue

2.apersonwhostudiesinsects:

entomologist

3.anitemthatisanexampleofalargergroup:

specimen

4.destroycompletely;causetonolongerexist:

wipeout

5.ascientificinstrumentthatuseslensestomakesmallobjectsappearlarger:

microscope

6.thematerialthatcarriesthegeneticinformationinthecellsofeachlivingthing:

DNASUMMARY

ThemysteryoftheRockyMountainlocusthasbaffledscientistsinNorthAmericaforover100years.AfterlocustscompletelydevastatedmanypartsoftheUnitedStatesin1875,theentirespeciesvanishedfromthecontinent.EntomologistJeffLockwoodisdeterminedtosolvethismystery.AftertravelingtotheRockyMountainsandstudyinglocustsfrozeninglaciers,Lockwoodbeginstolookatthemysteryfromanewangle.Warmingup

TeachingNOTES

1.Showstudentssomepicturesoflocustsfromthereadingpassageorothersourcesyoucanfind.

2.Havestudentsguesswhythelocustsinthisvideoandthereadingpassagearecalledtheperfectswarm.

3.Askquestionslike“Haveyoueverseenalocust”and“Whatdoyouknowaboutlocusts

Grasshopper

Therearehundredsofspeciesofgrasshoppers.TheseinsectsbelongtothesuborderCaeliferaintheorderOrthoptera,andhaveantennaethatarealmostalwaysshorterthantheirbodies,andshortovipositors—organs

forlayingeggs.Normallyfemalesarelargerthanmales.Maleshaveasingleunpairedplateattheendoftheabdomen.Thetwopairsofvalves（triangles）attheendofthefemaleabdomenareusedtodiginsandbythefemalegrasshopperwhenlayingeggs.

Althoughtheydifferinmanyfeatures,theyareeasilyconfusedwithanothersub-orderofOrthoptera,Ensifera.Themaindistinguishingelementsarethenumberofsegmentsintheirantennaeandstructureoftheovipositor.Thelocationofthetympanaandmodesofsoundproductionareotherdistinguishingfeatures.Ensiferanshaveantennaewithatleast20—24segments,andCaeliferanshavefewer.

Butterfly

Likeotherholometabolousspecieswithacompletemetamorphosiswheretheimmatureinsectsareentirelydifferentfromthematurestages,butterfliesecyclegoe'sthlirfoughfourstages:

egg,larva,pupaandadult.Theirwingsarelarge,oftenbrightlycolored,andtheyhaveconspicuous,flutteringflight.

Butterfliescomprisethetruebutterflies,theskippersandthemoth-butterflies.TheverymanyotherfamilieswithintheorderLepidopteraareconsideredmoths.Somebutterfliesmigrateoverlongdistances.Somehaveformedsymbioticandparasiticrelationshipswithsocialinsectssuchasants.Butterfliesareimportanteconomicallyasagentsofpollination.Afewspeciesarepestsbecausetheycandamageagriculturalcropsortreesintheirlarvalstages.

Culturally,butterfliesarefeaturedinthevisualandliteraryarts.

Dragonfly

Adragonflyisaninsectcharacterizedbybigmultifacetedeyes,twopairsofstrongtransparentwings,andanelongatedbody.Dragonfliesanddamselfliesaresimilarindifferinthepositionoftheirwingswhichareheldawayfrom,andperpendicularto,thebodywhenatrest.Likeanyotherinsects,dragonfliespossesssixlegs,butarenotabletowalk.

Dragonfliesusuallyeatflies,bees,ants,butterflies,andothersmallharmfulinsects,andarevaluableaspredatorswhohelpkeeptheequilibriumbetweenbeneficialinsectsandusuallylivearoundlakes,ponds,streamsandwetlandsbecausetheirlarvae,knownas“nymphs”,areaquatic.

Cricket

Partiallyrelatedtograsshoppers,cricketsareanothergroupofinsectswithlongantennaeandflattenedbodies.Theyhavegoodvisionandhearing.Theircompoundeyesenablethemtoseeinseveraldirectionssimultaneously.Alargenumberofcricketsdonotflybecausetheirwingsarenotfullydeveloped,butlieacrosstheback.Theirabilitytojumptogreatheightscompensatesforthelackofflyingskills.Cricketsnormallylivelessthanoneyear.Inthespring,thenascentinsecthatchesandlooksliketheadult,exceptforthewings.Onlyaftersheddingtheskinseveraltimesdocricketsdevelopnewwings.

Althoughnotallkindsofcricketsarepests,somespeciessuchastheblackfieldcricketcanaffectcropsandgardens.Theycanalsoattackdwellingsinautumn.Thepalegreentreecricketcandestroytwigsandberrycanes.

Insomecultures,itissaidthatcricketsbringgoodluck.Somepeoplebelievethatallthosewhoarefortunateenoughtoheartheirsongsareblessed.Ifacricketlivesinthehouse,itistreatedwithrespect.Theyareplacedinsmallcagesandgivenfoodandwaterastheinhabitantsofthehousethinkthattheirexistencebringsgoodfortune.

Watching

videoSCRIPT

slocus

Itcameover

Narrator:

Damagefromswarmsoflocustscanreachdisastrousproportions.Asingleswarmofdesertlocustscanconsumeover70,000metrictonsofvegetationaday.Thereis,however,onecontinentthat-free:

NorthAmerica.

Interestinglyenough,thiswasn'talwaystrue.Forhundredsofyears,theRockyMountainlocustwasacommonpestintheAmericanWest.Backinthemid-1800s,thousandsofpioneersjourneyedacrossthe.insearchoffreelandandnewopportunities.Theysettledonthefrontierofthewesternstates,andbegantofarmthelandintensively,growingcornandothercrops.

Then,in1875,outofnowhere,ararecombinationofaircurrents,drought,andbasicbiologyproducedtherightconditionsforanunthinkableevent,theworststormeverrecorded,the“perfectswarm.

horizonlikeastrange,darkcloud.Notmillions,notbillions,buttrillionsofinsects,sweepingthroughthelandlikealivingtornado.Thosewhosawtheincredibleeventandsurvivedneverforgotwhattheywitnessed.

TheswarmcametogetheroverthestateofTexas,andsoonmovedquicklyacrossthefrontierinahugedestructivecloudthatwasnearly3,000kilometerslong.ThestormspreadnorthtowardsNorthDakota.ThelocustseventuallywentasfarwestastheRockyMountains,leavingapathofdevastationanddestructionwherevertheywent.

Anaccountfromonepersonwhoobservedtheswarmdescribedthelocuststorm.Thelocustscamedownfromtheskylikehail.Frightenedpeopleranscreamingintotheirhomesasthelocusts'clawsdugintotheirsk

andhungupontheirclothing.Theyheardsharpcracksastheinsectscameunderfoot.Thelargelocustswereeverywhere,lookingwithhungryeyesturningthiswayandthat.Theirbodiesblockedthesun,bringingdarknessalongwiththedestruction.

Cropdamageswereabsolutelyastonishing.IfsuchdestructionweretohappentodayitwouldcostanestimatedUS$116billion,morethanthemostcostlyhurricaneinAmericanhistory.Andthen,somethingremarkablehappened:

theRockyMountainlocustsimplyvanished.

AttheUniversityofWyoming,entomologistDr.JeffLockwoodhasspentoveradecadeinvestigatingwhytheRockyMountainlocustdisappeared.

Dr.JeffLockwood,UniversityofWyoming:

“Therewereprobablymorelocustsinthelargestswarmthanthere

arestarsintheMilkyWay—trillions.Notonlyissomethingofthatscaleandmagnitudeandpowergone,butit'sgonewithinafewyears.It'snottraesmifewnedohuasdsaeriesofearthquakesortidalwavesorforestfires.

Andsoitdoesn'tmakesensethatitcould'vegoneextinct.There'snoreasonforittohavedoneso.It

mystery.”

Narrator:

It'asmysterythatLockwoodisdeterminedtosolve.WhateverwipedouttheRockyMountainlocustchangedAmericanhistor