Let's get a picture of us with the sea in the background. ✬

There is a castle in the background of the picture. ✬

Who is that man in the background of the picture? ✬

If someone who doesn't know your background says that you sound like a native speaker, it means they probably noticed something about your speaking that made them realize you weren't a native speaker. In other words, you don't really sound like a native speaker. ✬

Tom had his picture taken with Mt. Fuji in the background. ✬

Let's check Tom's background. ✬

What's that noise I can hear in the background? ✬

The portrait had a dark background. ✬

I checked on Tom's background and he seems to be a well-respected man. ✬

Did you do a background check? ✬