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.

Hank, are you arresting me?
Sky--
Breaking Bad Season 5, Episode 10

where the sun was in the SKY when
you knocked Balon Swann from his horse,
Game of Thrones Season 2, Episode 7

Smoke rising into the SKY.
Game of Thrones Season 4, Episode 4

He came from the SKY and...
Game of Thrones Season 4, Episode 10