In the past, persons referred to a specific number of individuals, whereas people was used in a more general sense. 

过去，persons指具体数量的人，而people用来表达更加笼统宽泛的意思。

You would not use persons in reference to groups of large or indeterminate size, such as a room full of students, the crowd at a football game, or the population of Sudan.

表达指代较大数量人群或不确定数量的人群时，不可以用persons。例如，充满学生的屋子，足球比赛的观赛人群，或者苏丹的人口。

Today, the use of persons has narrowed to specific phrases, usually in a legal or law enforcement context.

现在，persons的用法变得更加有限，只在个别短语中使用，通常是法律法规的条文中。

If you have a small, specific number, like three bank robbers or two runaway children, you might choose to say persons of interest or missing persons instead, as the case may be.

如果你想表达的是一个较小的、具体的数字，比如三个银行劫匪或者两个走丢的孩子，你可以说persons of interest (嫌疑犯)，或者missing persons（走丢人口）。

例如：

The police are searching for three persons of interest in connection with the armed robbery of a bank Tuesday night.

警方正在搜寻与周四的银行持械抢劫案有关的几名嫌疑犯。

Outside of these situations, persons is not commonly used.

除开以上这几种情况外，persons一般很少用到。