白云苍狗 [bái yún cāng gǒu]汉语成语白云苍狗(bai yun cang gou ),成语,指浮云像白衣裳,顷刻又变得像苍白色的狗,比喻世事变幻无常。中文名白云苍狗外文名The changes in human affairs often take freakish forms解释比喻事物变化不定出自唐·杜甫《可叹诗》语法联合式;作主语、宾语