小時了了，大未必佳 [－时－－－－－－－]

Jyutping siu2 si4 liu5 liu5, daai6 mei6 bit1 gaai1
Pinyin xiǎo shí liǎo liǎo , dà wèi bì jiā

Definitions (CC-CEDICT)
  1. being bright at an early age does not necessarily bring success upon growing up (proverb)