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.

Surprise.
The Big Bang Theory Season 1, Episode 16

ALL:
Surprise!
Breaking Bad Season 2, Episode 3

No, I thought
that'd be a nice SURPRISE for her.
The Big Bang Theory Season 3, Episode 5

Well, thank you, Sheldon,
this is a fun SURPRISE.
The Big Bang Theory Season 10, Episode 6

♪ Ain't no big SURPRISE ♪
The Big Bang Theory Season 7, Episode 3