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.

So who's your CHIEF,
little Injun?
Breaking Bad Season 2, Episode 3

and I was delighted to learn that
their CHIEF agricultural product is sod.
The Big Bang Theory Season 10, Episode 23

{\i1}and the Chief of the Defense Staff.{\i0}
Money Heist Season 3, Episode 5

My brother's a police CHIEF.
Breaking Bad Season 3, Episode 8

{\i1}The Minister of the Interior,{\i0}
{\i1}the Chief of the Defense Staff,{\i0}
Money Heist Season 3, Episode 5