完整word版《新世纪研究生公共英语教材阅读A》课文.docx
《完整word版《新世纪研究生公共英语教材阅读A》课文.docx》由会员分享,可在线阅读,更多相关《完整word版《新世纪研究生公共英语教材阅读A》课文.docx(14页珍藏版)》请在冰豆网上搜索。
![完整word版《新世纪研究生公共英语教材阅读A》课文.docx](https://file1.bdocx.com/fileroot1/2022-11/19/47c78ad8-158e-4009-9376-85abc4095c8a/47c78ad8-158e-4009-9376-85abc4095c8a1.gif)
完整word版《新世纪研究生公共英语教材阅读A》课文
《新世纪研究生公共英语教材阅读A》课文
Unit3OceanofSand
FromTheGuardian
1.Thereismoredesertsthansunandsand。
Onthesetwopagesyoucanfindouthowplants,animalsandpeoplemanagetosurviveintheseapparentlybarrenplaces。
2.Alldesertsaredry。
Thehot,sandyplaceswethinkofwhenwetalkaboutdesertsaresubtropicaldeserts。
TheyarefoundneartheTropicsofCancerandCapricornwherethewarmairwhichrisesattheEquatorsinksdownagain,givingaclimateofclearskiesandverylowrainfall.TheSaharaisalmostone-thirdthesizeofAfrica,andisnearlyasbigastheU.S.A.,thefourthlargestcountry.Itwasnotalwaysadesert.Overmillionsofyearsithasbeenconveredinice,sea,forestsandgrasslands.
3.Desertwindsareusuallydry.Somedesertsarein“rainshadow”areaswherethewindshavelostwhatmoisturetheyhadcrossinghighground。
Othersareinthemiddleofcontinentswherethewindsblowingoverthemhavelostanymoisturegainedfromdistantoceans.TheGobidesertinMongoliainAsiaisanexampleofsuchaninlanddesert.TheAtacamainnorthernChileisthedriestdesertonEarth。
Partsofthedeserthadnorainfor400years,from1570to1971,andinotherparts,rainshadneverbeenrecordedn.OneofthesandiestdesertsistheTaklaMakan。
Sandstormscanwhipupthesandashighas3,048m(10.000ft)。
WindblownsandintheSaharacanbesofiercethatitwillsandblastthepointoffacaroraeroplane.Thetemperatureatnightinahotdesertcandropbelowfreezing,to-4℃(24℉).Duringtheday,thesandcanbeashotas79℃(175℉)。
Livinginadesertclimate
4.Desertsaredifficultplacesinwhichtolive.Duringthedaytheyareveryhot。
IntheLibyanDesertinNorthAfricathetemperatureon13September1922reached58Cintheshade!
Butdesertnightsareoftencoldbecauseclearskiesallowheattoescapeintotheatmosphere。
Thelackofwatercausedbylowrainfallisbadenough,butrainfallisalsohighlyunpredictable。
Yearsofdroughtcanendintremendousrainstorms。
Manydesertareasarebarerock,orarecoveredwithpebblesandgravel.Sandaccountsforonlyabout15percentoftheearth'sdesertregions.Insomedeserts,thetotalrainfortheyearmightfallinonlytwoorthreestorms.Butthatisenoughforplantseedstosproutandbloom,turningpartsofthedesertintocarpetsofflowersforafewdays。
Howplantssurvive
5.Withinafewhoursofrainfalling,thousandsoffloweringplantswillstarttoappear。
Seedsofplantssuchasthedesertdandelionlieinthegroundforyearswaitingfortherain。
6.Theseplantsdieasthedesertdriesoutagain,leavingtheirseedsforthenextrains。
Otherplantshaveadaptedtotheharshenvironmentbystoringwaterintheirleaves,stemsorroots。
TheAmericansaguarocactuscanhold6to8tonesofwater.Desertplantsoftenhavespreadingrootsystemswhichextracteverydropofmoisturefromtheground.Therootsofthemesquitebushcanbe20mdeep.
7。
Plantsgenerallylosewaterthroughporesintheirleaves.Topreventthis,desertplantshavesmallwaxyleavesandfewerpores。
Manyclosetheirporesduringthedaysotheydonotlosemoisture.Toprotectthemselvesagainstgrazinganimals,someplantshavethornsoranunpleasanttaste。
Cactiareprotectedbytheirsharpspines.CactiarefoundonlyinAmericandeserts.Thetallestaresaguaroswhichcanreach15m(50ft)tall,weigh7tonsandlivefor200years.Waterisstoredinthestemandusedintimesofdrought.
Animallife
8.Althoughdesertsseemempty,fewarewithoutanimals.Mostanimalsshelterfromthedaytimeheatinholesorburrows.Theburrowstrapmoisturearestaycoolerthanthegroundabove。
Inthecoolereveningoratdawn,theanimalsemerge.
9.Smallermammalsoftenhavelargeears.Duringtheday,theanimallosesheatthroughitsears。
Inthedark,largewarntheanimalofunseendangers.
10.Reptilesventuringoutindaytimetrytoavoidtouchingthehotsand。
TheAustralianbeardedlizardsometimesrunsonitshindlegsonly.Theaptlynamedsidewindersnakeonlytouchesthegroundintwoplaces。
11.Alldesertanimalssurviveonlittlewater.Manysmallanimalsliveonthemoistureintheirfood.Largeranimalssuchasthecamelcangowithoutwaterfordays,butdrinkhugeamountswhentheygetthechance.Acamelcandrink10litresofwaterinaminute.
Desertpeoples
12.Overthoughtofyears,peoplehavelearnthowtosurviveinDeserts.TheSanpeopleoftheKalaharidesertinsouthernAfricaandtheAustralianAborigineshuntanimalsandgatherfoodplants。
Theylearntraditionalskillsfromolderpeople.
13.Ontheedgesofthedesert,nomadicpeoplesgrazeflocksofsheepandgoats。
Theyareconstantlymovingtofresherpastures.NomadssuchastheTuaregoftheSaharainNorthAfricawearloosechothingtoprotectthemsandandheat。