xí fù áo chéng pó
lit. even a submissive daughter-in-law will one day become a domineering mother-in-law (idiom)
fig. the oppressed will become the oppressor; what goes around comes around
媳
xí
daughter-in-law
妇
fù
woman
熬
áo
to cook on a slow fire; to extract by heating; to decoct
成
chéng
short name for Chengdu 成都[Cheng2 du1]
婆
pó
(bound form) grandmother