冰凍三尺,非一日之寒

bīngdòngsānchǐfēiyīrìzhīhán ㄅㄧㄥ ㄉㄨㄥˋ ㄙㄢ ㄔˇ ㄈㄟ ㄧ ㄖˋ ㄓ ㄏㄢˊ

    • Rome wasn't built in a day great changes result from long accumulation

      figurative

Sources