【導(dǎo)讀】andsawfarmsthatcoveredthousandsofacres.Afrerdinner,theywerebackinanurbanarea,thebusyportcityofThunderBayatthetopoftheGreatLakes.BecauseoftheGreatLakes,theylearned,Canadahasmorefreshwaterthananyothercountryintheworld.Infact,ithasone-thirdoftheworld?stotalfreshwater,andmuchofitisintheGreatLakes.Thatnightastheyslept,thetrainrushedacrossthetopofLakeSuperior,throughthegreatforestsandsouthwardtowadsToro