形容詞 precocious:

1. characterized by or characteristic of exceptionally early development or maturity (especially in mental aptitude)
2. appearing or developing early

1. Childhood hardships matured in him a precocious sense of responsibility.
   童年的艱苦生活使他提早形成了一種過早具有的責任感。
2. That child is far too precocious.
   孩子過于老成。
3. His son is a precocious child who could play the piano at the age of three.
   他的兒子是一個三歲就能彈奏鋼琴的早慧兒童。

pre.co.cious

adj.（形容詞）
Manifesting or characterized by unusually early development or maturity, especially in mental aptitude.
早熟的：表明或以不尋常的過早發(fā)展或成熟為特點的，尤指智力
Botany Blossoming before the appearance of leaves.
【植物學】 早開的：葉子出現(xiàn)之前開花的

來源：
From Latin praecox praecoc- [premature]
源自 拉丁語 praecox praecoc- [早熟的]
from praecoquere [to boil before, ripen fully]
源自 praecoquere [先于…沸騰的，熟透的]
prae- [pre-]
prae- [前綴，表.先于.]
coquere [to cook, ripen] * see pek w-
coquere [燒，成熟] *參見 pek w-

【引伸】
preco.ciously
adv.（副詞）
precoc.ity