摘要
Thesemightyfallsareoneofthegreatnaturalwondersoftheworldalthoughtheyarenot,infact,nearlythehighestintheworld-theKaieteurFalls,forinstance,inBritishGuianabeingfivetimesashigh.TheyarepartlyinCanadaandpartlyintheUnitedStates,astheboundarybetweenthetwocountriesfollowstheRiverNiagara.ThisflowsfromLakeErieintoLakeOntario,andinitscourse
出版日期
2003年12月22日（中国期刊网平台首次上网日期，不代表论文的发表时间）
