one in a million 和one out of a million有何区别

两者区别不大：one in a million = one out of a million，本意是“每百万...就有一个/百万分之一”，只不过前者可以引申为“凤毛麟角，百/万里挑一，佼佼者”的意思。

例如：

1. .I want to introduce you to a person who is one in a million.

我要介绍给你的人可真正是百里挑一的啊。

2. The millions are awake enough for physical labor ; but only one in a million is awake enough for effective intellectual exertion , only one in a hundred millions to a poetic or divine life.

几百万人清醒的足以从事体力劳动，但是一百万人中，只有一个人才清醒的足以有效的服役于智慧;一亿人中，才能有一个人，生活的诗意而神圣。

3. Only about one out of a million cells will correctly incorporate a foreign gene using the most common versions of this technique.

应用这种最常规的技术，仅有百万分之一的细胞可以正确加人外源基因。