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.

Oh, Amy's at the dry-cleaner's
and she's made a very amusing PUN.
The Big Bang Theory Season 4, Episode 1

Pun intended?
The Big Bang Theory Season 4, Episode 20

I'm sorry. What PUN?
The Big Bang Theory Season 4, Episode 20

Pun intended?
The Big Bang Theory Season 4, Episode 20