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.

Three hundred TWENTY dollars
a bottle.
Breaking Bad Season 4, Episode 3

I don't think you could ride the dragon.
Twenty years ago, maybe.
Game of Thrones Season 6, Episode 4

Twenty fucking years.
Game of Thrones Season 5, Episode 8

Twenty seconds.
The Big Bang Theory Season 4, Episode 21

Twenty seconds.
Money Heist Season 3, Episode 4