Dujiangyanistheoldestman-madewatersystemintheworld,anda...
问题详情：Dujiangyanistheoldestman-madewatersystemintheworld,andawonderinthedevelopmentofChinesescience.Builtover2,200yearsagoinwhatisnowSichuanProvinceinSouthwestChina,thisamazingengineeringachievement...