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 have many guards who'd
happily IMPRISON him or behead him
Game of Thrones Season 7, Episode 6

and you let a band of fanatics
IMPRISON your brother-by-law.
Game of Thrones Season 5, Episode 4

I didn't IMPRISON anyone.
Game of Thrones Season 5, Episode 6

How did my sweet sister persuade the king
to IMPRISON his dear friend Ned?
Game of Thrones Season 1, Episode 8