遡流求源

Explanation: With the "Soo flow poor source." "Yuan Shi Du Ying Chuan seclusion": "Cardiff is not necessarily good beginning hospice, now can not find the source stream Soo Ming law is vulgar, Xinghua sterile timber to save a hundred thousand evil, harm servant fear after the date of the There can not win the speaker carry on. " Thesaurus:  Suliucuyuan, Upstream Poor source