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're a fucking VIRUS!
Westworld Season 2, Episode 9

They got, like, this rage VIRUS,
Breaking Bad Season 4, Episode 2

with an unknown VIRUS!
Money Heist Season 3, Episode 4

I think it's got a VIRUS
from all the...
The Big Bang Theory Season 11, Episode 9

What would a West African VIRUS
be doing in our lab?
Breaking Bad Season 3, Episode 10