Treesareusefultomaninthreeimportantways:theygivehimwood...
問題詳情：Treesareusefultomaninthreeimportantways:theygivehimwoodandotherusefulthings,theygivehimcoolplaces,andtheyhelptostopdroughtandflood.Unluckily,inmanypartsoftheworld,manhasnotfoundthatthethirdoft...