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.

Spoiler alert: we don't.
The Big Bang Theory Season 11, Episode 10

Spoiler, works.
The Big Bang Theory Season 10, Episode 20

Oh, SPOILER alert.
He was worried about nothing.
The Big Bang Theory Season 8, Episode 7

Spoiler alert:
it was fine.
The Big Bang Theory Season 12, Episode 14

Spoiler, way.
The Big Bang Theory Season 10, Episode 20