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.

I've been in the CAPITAL a month.
Game of Thrones Season 1, Episode 5

to come here to the CAPITAL.
Game of Thrones Season 3, Episode 7

Welcome to the CAPITAL.
Game of Thrones Season 4, Episode 7

What did I once tell you about the CAPITAL?
Game of Thrones Season 4, Episode 3

After he was executed, I fled the CAPITAL.
Game of Thrones Season 5, Episode 6