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.

So now let's bring out theoretical PHYSICIST,
Dr. Sheldon Cooper!
The Big Bang Theory Season 6, Episode 18

Uh, I am an experimental
PHYSICIST at Cal-Tech,
The Big Bang Theory Season 5, Episode 13

He's an engineer
and I'm an experimental PHYSICIST.
The Big Bang Theory Season 4, Episode 7

Of course not.
I'm a theoretical PHYSICIST.
The Big Bang Theory Season 2, Episode 23

She's a neurobiologist, and
I'm a theoretical PHYSICIST.
The Big Bang Theory Season 7, Episode 21