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.

What, like a witness PROTECTION
kind of thing?
Breaking Bad Season 4, Episode 4

You kids better use PROTECTION.
The Big Bang Theory Season 6, Episode 1

Because if it's just
personal PROTECTION,
Breaking Bad Season 4, Episode 2

If the Lannisters were to order attacks
on villages under the king's PROTECTION,
Game of Thrones Season 1, Episode 6

They are grateful for your PROTECTION
within the walls of the Red Keep.
Game of Thrones Season 8, Episode 4