Windwaterfireandice-thesepowerfulnaturalforceshaveshapedthelandofAmericainthepast.Theyarestillchangingittoday.
TheColoradoRiverslowlycutdownthroughstonetomaketheGrandCanyon(大峡谷).
LongagoicesheetscutYosemiteValleyandtheGreatLakesandglaciers(冰川)arestillonthemoveinAlaska.
Windandrainstormhitthelandfromtimetotime.Firessometimesburndownforestsanddestroythehomesofwildanimals.ThishappenedinYellowstoneParkin1988.
DeadvolcanicmountainssuchasHaleakalaonMauiandCarterLakeinOregonarebeautifultolookat.ButthereareseveralactivevolcanoesintheUSespeciallyalongthePacificCoast.Therearealsomanyearthquakesinthisarea.Scientistscandonothingtocontrolearthquakesorvolcanoes.ThiswasshownclearlyonMay181980.At8:32thatmorningMountStHelensinWashingtonstatebrokeout.Thetopofthemountainwasblownoff.
Over60people–campersscientistsjournalistsforestworkers—werekilled.Hundredsofsquaremilesofforestswereknockeddown.Intownsover100milesawaydaysuddenlybecamenight.Anashcloudhidthesunformanyhours.TownsandfieldsinWashingtonOregonandIdahowerecoveredwithdirtygrayash.
ScientistsknewthatMtStHelensmighterupt(爆发)soon.Butnoonecouldsaywhen.Andnooneexpectedtheterriblestrengthoftheeruption.Manypeopleweresurprisedandunready.HarryR.Truman84ownedasmallhotelinMtStHelens.Scientistshadaskedpeopletomoveawaybecausethevolcanowasbecomingdangerous.
ButHarryTrumanwouldnotleavehishome.Nowitiscoveredwithmanyfeetofdirtyash.AsmallcrossstandsabovetheplacewhereHarryprobablydied.PerhapsitisbetterthathedidnotseethedestructionofMtStHelenstheoncebeautifullakeandtheforests.
Butslowlylifeisreturningtothedeadareaaroundthemountain.Grassandsmallplantsarebeginningtogrowagain.Deerandbirdshavebeenseen.Thelandwillneverbethesameasitoncewas.PerhapsMtStHelenswilleruptagain.Butthisisallpartofnature’spatternofchangeandmanhaslittlepowertocontrolit.
1.Choosethebesttitleforthispassage.