用绳测井深，把绳三折，井外余2米，把绳四折，还差1米不到井口，那么井深;?'n/q+}2u4p:G9z*V4l:W4N)^+`3{米，绳长0u;H9W:v7|/]+q米。,o2G'Y;f7?2q9z7Y0i