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.

...but didn't because there were
CRACKER crumbs on it.
The Big Bang Theory Season 8, Episode 1

Holy crap on a CRACKER.
The Big Bang Theory Season 2, Episode 6

...and we're being offered a CRACKER
to quench our thirst.
The Big Bang Theory Season 2, Episode 18

Holy crap on a CRACKER.
The Big Bang Theory Season 2, Episode 6