【Itisnicetoknowwhattheweatherwillbelikewhenweplanatrip.Doyouknowanythingaboutthehistoryofweather?Don’tlookatthesky.Don’tlookforoldweatherreports.Lookingatthetreeringsismoreimportant.Correctweather】

　　Itisnicetoknowwhattheweatherwillbelikewhenweplanatrip.Doyouknowanythingaboutthehistoryofweather?Don’tlookatthesky.Don’tlookforoldweatherreports.Lookingatthetreeringsismoreimportant.Correctweatherreportsdatebackonlyonecentury,butsometreescanprovideanexactrecordofweatherevenfurtherback.

　　Itisnaturalthatatreewouldgrowbestinaclimatewithplentyofsunlightandrainfall.Itisalsoexpectedthatlittlesunlightorrainfallwouldreducethegrowthofatree.Thechangefromafavorabletoanunfavorableclimatecanbefoundoutbythereadingpatternofringsinatreetrunk.Tofindouttheweatheroftenyearsago,youcancounttheringsofatreetrunkfromtheoutsidetotheinside.Ifthetenthringisfarfromtheotherrings,thenitiscertainthatplentyofsunnyandrainyweatheroccurred.Iftheringsareclosetogether,thentheclimatewasbadforthetree.

　　Studyingtreesisimportantnotonlyforthehistoryofweather,butalsoforthehistoryofman.InanareaofNewMexicoyoucanfindonlysand—notreesorpeople.However,manycenturiesagoalargepopulationlivedthere.Theyleftsuddenly.Why?

　　Ascientiststudiedthepatternoftheringsofdeadtreesthathadgrownthere.Hemadeuphismindthatthepeoplehadtoleavebecausetheyhadcutdownallthetrees.Treeswerenecessarytomakefiresandbuildings.So,afterthepeopledestroyedthetrees,theyhadtomove.

　　Inthisexamplestudyingtreeringsuncoveredanexcitingfactaboutthehistoryofman.

　　小题1:Wecanfindouttheweatheroffiveyearsagobycountingtheringsofatreetrunk____.A．fromthelefttotherightB．fromtherighttotheleftC．fromtheinsidetotheoutsideD．fromtheoutsidetotheinside小题2:Iftheringwasfarfromtheothers,wecanconcludethattheweatherofthatyearwas______.A．badB．sunnyC．favorableD．rainy小题3:BystudyingtheringsofdeadtreesinanareaofNewMexico,thescientistfound_______.A．whythepeoplehadtoleaveB．wherethepeoplehadtogoC．whatthepeoplehadtoeatD．howth