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.

I'm an ADVOCATE of mitosis.
The Big Bang Theory Season 2, Episode 6

Just saying. Devil's ADVOCATE.
Breaking Bad Season 3, Episode 9

Skyler, I'm your biggest ADVOCATE here,
and I'm telling you, for your own good,
Breaking Bad Season 5, Episode 10