Dujiangyanistheoldestman-madewatersystemintheworld,anda...
問題詳情：Dujiangyanistheoldestman-madewatersystemintheworld,andawonderinthedevelopmentofChinesescience.Builtover2,200yearsagoinwhatisnowSichuanProvinceinSouthwestChina,thisamazingengineeringachievement...