Thegroundwewalkonseemsfirm,butdeepundertheearthandunder...
問題詳情：Thegroundwewalkonseemsfirm,butdeepundertheearthandundertheseatherockschangeandmove.Insomepartsoftheworldthereare“firemountains”，whichwecalltimetotimetheyburstopenandthrowoutfireandburningash....