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.

Why wouldn't that Colonel say
what the meeting is about?
The Big Bang Theory Season 10, Episode 1

Maybe we should pitch it
to Colonel Williams today.
The Big Bang Theory Season 11, Episode 8

Colonel, you've just joined us,
so allow me to remind you what
Money Heist Season 3, Episode 4

Colonel, I'm recording this conversation.
Money Heist Season 3, Episode 4

Colonel.
Money Heist Season 1, Episode 11