无法更改的事实；

1. It is a fact of life and you must face it.
    这是严酷的现实，你必须面对它。

1. 无法更改的 事实：Facts are stubborn. [谚]事实是不可否认的. | fact of life 无法更改的 事实 | 现代英汉词典fact

1. (令人不快却又无法改变的)生活现实
    You say that something which is not pleasant is a fact of life when there is nothing you can do to change it so you must accept it.

    e.g. 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。

2. (教给儿童的)性知识
    If you tell a child about the facts of life, you tell him or her about sexual intercourse and how babies are born.

    e.g. 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。