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.

Hey, Leonard, you LEFT your underwear
in the drier downstairs.
The Big Bang Theory Season 1, Episode 15

Left.
Money Heist Season 1, Episode 5

I've LEFT all kinds of messages
on his voicemail,
Breaking Bad Season 5, Episode 13

a couple years
after my dad LEFT.
The Big Bang Theory Season 7, Episode 18

- I still don't know why you LEFT.
- I can't tell you.
The Big Bang Theory Season 2, Episode 1