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.

The next CLUE
must be hidden
The Big Bang Theory Season 7, Episode 3

What was your first CLUE?
The Big Bang Theory Season 3, Episode 7

Can you reach the CLUE?
The Big Bang Theory Season 7, Episode 3

running all over town searching
for the next CLUE,
The Big Bang Theory Season 12, Episode 2

Maybe the spot's
the CLUE.
The Big Bang Theory Season 7, Episode 3