wet behind the ears
缺乏經驗或成熟，年輕且無知
口語·批評缺乏經驗
英文釋義
lacking experience or maturity; inexperienced or naive
例句
Don't trust him with the project; he's still wet behind the ears.
典故來源
源自動物幼崽出生時耳朵潮濕，比喻人缺乏經驗、稚嫩。