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.

My wife must be LONELY.
Game of Thrones Season 5, Episode 10

...but let's face it, that's just a smaller
LONELY room filled with comic books.
The Big Bang Theory Season 3, Episode 7

The LONELY guy
and the two happy couples?
The Big Bang Theory Season 4, Episode 22

Are you LONELY?
Game of Thrones Season 5, Episode 4

Hello, I wanna talk about
how LONELY I am, too.
The Big Bang Theory Season 9, Episode 15