1.know about 知道，了解

Here are a few facets you might not know about.
但有些事情你可能未必知道。

Everything I know about it I picked up from the same sources you did.
对于该动向，我了解信息的渠道与各位完全一样。

2.heard about 听说

Most heard about 1989 from their parents or high school teachers.
多数人都从自己的父母或高中老师那里听说过1989年的事件。

We've all heard about antioxidants as cancer fighters.
我们都听到过抗氧化剂是抗癌斗士的说法。