- 问题详情:Inthe1960s,whilestudyingthevolcanichistoryofYellowstoneNationalPark,BobChristiansenbecamepuzzledaboutsomethingthat,oddly,hadnottroubledanyonebefore:hecouldn'tfindthepark'svolcano.IthadbeenknownforalongtimethatYellowstonewasvolcanicinnature—that...
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