They talk behind your back.

他们在你背后谈论。

youdao

Don't talk behind people's backs.

不要在别人背后说别人的坏话。

youdao

They talk behind you and say unpleasant things.

他们在你身后议论，谈些让你不快的事情。

youdao

So "I was" will be used to talk about anything that you're referring to that's behind you.

所以，“I was” 会被用来谈论那些你曾经做过的事情。

I was 课堂 - SpeakingMax英语口语达人

Sure, players will talk behind each other's backs, not necessarily in a disparaging way, but -- to the outside world at least -- the team is a united front.

CNN: SHARE THIS

For all the year's talk and behind-the-scenes beltway battles about how best to revise financial market regulations, there's been little official public debate.

FORBES: Magazine Article

If you talk to people behind the scenes they will tell you that was the real Anna Kournikova.

BBC: Kournikova close to the edge