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.

Uh, OCCUPATIONAL hazard.
Breaking Bad Season 2, Episode 11

...OCCUPATIONAL therapy,
medical equipment.
Breaking Bad Season 3, Episode 9

Oh, this is a-- I guess you'd call it
an OCCUPATIONAL hazard.
Breaking Bad Season 5, Episode 13