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.

Her dragons might not be
as INVULNERABLE as some think.
Game of Thrones Season 7, Episode 3

...and leaves the INVULNERABLE Kryptonian
fabric unharmed and daisy fresh.
The Big Bang Theory Season 2, Episode 11