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.

It'd be more hygienic
if they had a plague-infested GIBBON...
The Big Bang Theory Season 2, Episode 4

...and his sister just successfully grew
a human pancreas in an adolescent GIBBON.
The Big Bang Theory Season 2, Episode 15

Why else would you grow
a pancreas in a teenaged GIBBON?
The Big Bang Theory Season 2, Episode 15

But the GIBBON doesn't know
what it's categorized as.
The Big Bang Theory Season 8, Episode 8

Sorry, kid. You got it worse than a GIBBON.
The Big Bang Theory Season 8, Episode 8