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.

the entire upper LAYER
of infected tissue,
Game of Thrones Season 7, Episode 2

There’s a first LAYER made of steel
and a second one of reinforced concrete.
Money Heist Season 1, Episode 8

But the sign and tape are covered
with a LAYER of dust which indicates...
The Big Bang Theory Season 2, Episode 15

that the entire upper LAYER
of diseased skin was debrided,
Game of Thrones Season 7, Episode 3

erasing LAYER after LAYER.
Money Heist Season 3, Episode 4