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.

which I beat our daughter at
every SINGLE time.
The Big Bang Theory Season 12, Episode 9

-There's not a SINGLE drop of blood.
-Shoot me here, come on.
Money Heist Season 1, Episode 4

Dozens of hours spent on a SINGLE pair.
Game of Thrones Season 6, Episode 4

You've known him
for the space of a SINGLE conversation,
Game of Thrones Season 6, Episode 9

I don't think you'd understand
a SINGLE thing I was talking about.
The Big Bang Theory Season 8, Episode 2