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.

My milk stool is COMPLETE.
The Big Bang Theory Season 3, Episode 16

ANNOUNCER: (OVER PA)
Training exercise COMPLETE.
Westworld Season 3, Episode 8

is COMPLETE filth.
The Big Bang Theory Season 7, Episode 17

Okay, well, then you get
my COMPLETE lack of chill.
Breaking Bad Season 5, Episode 11

He's a COMPLETE stranger.
Breaking Bad Season 3, Episode 10