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.

Do you need it
to BUY a less disturbing sweater vest?
The Big Bang Theory Season 3, Episode 5

Sheldon, just BUY
scalped tickets with us.
The Big Bang Theory Season 7, Episode 14

Penny, if I'm going to BUY Leonard a gift,
I'm going to do it right.
The Big Bang Theory Season 1, Episode 16

This is silly. You don't need the car,
but you could BUY something else...
The Big Bang Theory Season 8, Episode 6

My plan is to stop at malls
and BUY what I need.
The Big Bang Theory Season 7, Episode 24