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.

All right, well, I don't
want to SPOIL anything,
The Big Bang Theory Season 12, Episode 14

"Spoiler alert.
When I see you I'm gonna SPOIL it."
The Big Bang Theory Season 9, Episode 19

Won't that SPOIL our appetites
The Big Bang Theory Season 5, Episode 6

But I didn't SPOIL anything.
The Big Bang Theory Season 2, Episode 22

They kind of SPOIL the ending
The Big Bang Theory Season 5, Episode 14