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.

We hide in the parking lot
and AMBUSH people when they come to pee.
The Big Bang Theory Season 2, Episode 16

How dare you AMBUSH my
girlfriend at the gym!
The Big Bang Theory Season 5, Episode 4

Hmph. A wildling AMBUSH.
Game of Thrones Season 1, Episode 1

We didn't mean
for it to be an AMBUSH.
The Big Bang Theory Season 5, Episode 4