fact of life

英 [fækt ɒv laɪf]

美 [fækt əv laɪf]

n. (令人不快却又无可奈何的)生活现实; (教给儿童的)性知识

Collins.1

柯林斯词典

N-COUNT (令人不快却又无法改变的)生活现实
You say that something which is not pleasant is afact of lifewhen there is nothing you can do to change it so you must accept it.
1. Stress is a fact of life from time to time for all of us.
  对我们所有人来说，精神压力常常是无从逃避的生活现实。
N-PLURAL (教给儿童的)性知识
If you tell a child aboutthe facts of life, you tell him or her about sexual intercourse and how babies are born.
1. There comes a time when children need to know more than the basic facts of life.
  是时候孩子们了解更多性知识了。