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.

Right now, you deal almost
exclusively with COCAINE.
Breaking Bad Season 4, Episode 8

So? Do COCAINE smugglers
write "COCAINE" on the box?
The Big Bang Theory Season 2, Episode 19

That's poor man's COCAINE.
Breaking Bad Season 4, Episode 8

So? Do COCAINE smugglers
write "COCAINE" on the box?
The Big Bang Theory Season 2, Episode 19

lt's stronger,
more addictive than COCAINE,
Breaking Bad Season 4, Episode 8