指报纸里的内容就用in,指东西放在报纸上用on

in the newspaper 在报纸上

例句：

I read about it in the newspaper.

我在报上看到了这件事。

相关介绍

I read instalments of the story in the newspaper last year.

我去年在报纸上读过这故事的分期连载。

I read every last article in the newspaper.

报纸上的每一篇文章我都读。

An article in the newspaper caught my attention.

报上一篇文章引起了我的注意。