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.

But we haven't
finished the PUZZLE.
The Big Bang Theory Season 7, Episode 3

Your next PUZZLE is a riddle.
The Big Bang Theory Season 7, Episode 3

Not the cube, but the PUZZLE of
why I couldn't solve the cube.
The Big Bang Theory Season 12, Episode 19

Apparently, he's 12-down in
the TV Guide crossword PUZZLE.
The Big Bang Theory Season 7, Episode 19

Relax, it's
a hard PUZZLE.
The Big Bang Theory Season 7, Episode 3