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.

You've been CLASSIFIED as terrorists,
so I got the CIA, Interpol,
Money Heist Season 3, Episode 5

What's CLASSIFIED?
The Big Bang Theory Season 2, Episode 22

It's full of CLASSIFIED information
about the Air Force project.
The Big Bang Theory Season 10, Episode 20

The gibbon is the only member
of the ape family not CLASSIFIED as a great ape.
The Big Bang Theory Season 8, Episode 8

All the non-human apes
are CLASSIFIED as great apes, except one.
The Big Bang Theory Season 8, Episode 8