出没不常

Explanation: There are no hidden rules, uncertain. 　　Source: Song Li Gang "and the Prime Minister to defend the thief of Sapporo son" build thief Qundao ratio of non-land, thousands of miles, according to re-ring the lake, haunted not often. " 　　Examples: Lake and therefore, Kou, ~. ★ Qing Shi Dai "Gao Feng Zhang Guanglu doctor of public epitaph"