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.

"It was obvious
there was a lack of women in the GANG."
Money Heist Season 1, Episode 1

Yes, these three were part of the GANG.
Money Heist Season 1, Episode 13

Hey. Shouldn't you be out with your GANG...
The Big Bang Theory Season 6, Episode 8

Gang of thieves, that's all this is.
Game of Thrones Season 4, Episode 9

onto the GANG of robbers who last Friday,
Money Heist Season 1, Episode 10