事過境遷

The issue is in the past, and the situation has changed (idiom). / It is water under the bridge.

matter / thing / item / work / affair / CL:件[jian4],樁|桩[zhuang1],回[hui2]

surname Guo

to cross / to go over / to pass (time) / to celebrate (a holiday) / to live / to get along / excessively / too-

(experienced action marker)

to pass through a country's territory / transit

border / place / condition / boundary / circumstances / territory

to move / to shift / to change (a position or location etc) / to promote