The best way to learn proper English is to read news report, and watch news on TV. Watching TV shows is a great way to learn casual English, slang words, understand culture reference and humor. If you have already watched these shows then you may recall the words used in the following dialogs.

Okay, imagine you're
looking in a MIRROR.
The Big Bang Theory Season 12, Episode 16

That's a MIRROR.
The Big Bang Theory Season 7, Episode 12

Space is the MIRROR of the soul.
The Big Bang Theory Season 11, Episode 14

Oh... I think we were looking at creepy in the
rearview MIRROR when I put up that camera.
The Big Bang Theory Season 6, Episode 21

It's like looking
into an obnoxious MIRROR, isn't it?
The Big Bang Theory Season 1, Episode 12