How well does he know his friends?

他对他的朋友有多了解？

youdao

But he says he and his two friends didn't really know much about the music business.

VOA: special.2010.04.19

Buscemi doesn't know if his friends back home will even get to see the film he's directed.

CNN: Main banner

All his friends know the songs.

FORBES: Where Have All The Rock Stars Gone?

If a user goes to a Sheryl Crow concert, for instance, his or her friends can know about it.

FORBES: Social Slingers