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.

They won't obey you
unless THEY fear you.
Game of Thrones Season 7, Episode 2

but THEY were geniuses.
Money Heist Season 3, Episode 2

-Do THEY all know what THEY have to do?
-They do! Of course THEY do!
Money Heist Season 1, Episode 5

Let them remember
what happens when THEY march on the South.
Game of Thrones Season 3, Episode 10

THEY randomly bumped into
each other at the DMV.
The Big Bang Theory Season 11, Episode 14