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1、1-2XUANXUANHelloeveryone,todayIwanttoshowyouapartofhowtheearthwasmade,andmainlytalkaboutYellowstone.Ascontinentsshiftandclash,volcanoeserupt,andglaciersgrowandrecede,theEarth'scrustiscarvedincountlessfascinatingways,leavingatrailofgeologicalmysteriesbehind・Andone
2、ofthegreatestisYellowstoneNationalParkinWyoming.Thisisoneoftheworld'smostgeologicallyactiveplaces,shakenbyupto5000earthquakeseveryyear,andwithmoregeysersandhotspringsthanintherestoftheworldcombined・ScientistsstudyingYellowstoneareuncoveringaviolentpast.Carvedwate
3、r,crushedbyancientglaciersandblastedbythebiggestvolcaniceruptionseverknownontheplanet.Andeventoday,YellowstoneisoneofthemostdangerousplacesonEarth.3LAOCAOYellowstoneisoneofthemostamazingplacesonEarth,andit9sunique・ItcontainssomeofAmerica'smoststunningsceneryandwi
4、ldlife.Yellowstoneistheworld'sfirstnationalparkwhichisinthenorthwesterncornerofWyomingandoverlapsintoMontanaandIdaho.Theparkcovers3468squaremiles,63milesnorthtosouthand54mileseasttowest.It'saveryunusualgeologythatcreatedthepark.Hundredsofspeciesofmammals,birds,fi
5、shandreptileshavebeendocumented,includingseveralthatareeitherendangeredorthreatened・Thevastforestsandgrasslandsalsoincludeuniquespeciesofplants・YellowstoneParkisthelargestandmostfamousmegafaunalocationintheContinentalUnitedStates.GrizzlyBears,wolves,andfree-rangi
6、ngherdsofbisonandelkliveinthepark.4-5JIEOldFaithfulisthestarattractionofYellowstone.It9soneofthemostpredictablegeographicalfeaturesonEarth,eruptingalmost91minutes・BeneathOldFaithfulisarathercomplexplumbingsystem,filledwithcavernsandconduitsandconstrictions.Rainwa
7、tersaturatingthegroundaroundthegeyserslowlyfillsitsundergroundreservoir.Hotrocksbelowgroundheatthewaterunderpressureforaround90minutes.Suddenlysomewaterspurtsthroughatiny,fiveinchwidecrackintherocks.Thiscausesadropinthepressurewithinthewaterchamber.Inainstant,tho
8、usandsofgallonsofwaterareturnedtosteamandblastedupintotheair.Thegasescomeoutfromthegeysersisthesamemixthatisfoundcomingoutofvolcanoes.Sogasesareclearevidenceth