I always got stuck on
the first CHALLENGE--
The Big Bang Theory Season 7, Episode 3
or a CHALLENGE to the system.
Money Heist Season 3, Episode 8
Maybe since you're so good,
he's taking his time to meet the CHALLENGE.
The Big Bang Theory Season 6, Episode 6
it was an unnecessary CHALLENGE
to our heterosexuality.
The Big Bang Theory Season 5, Episode 17
We've accepted the CHALLENGE.
We can't run away from a fight.
The Big Bang Theory Season 2, Episode 12