Penny, it's only NATURAL to want
your mother-in-law to like you,
The Big Bang Theory Season 9, Episode 23
I believe we are NATURAL allies.
Game of Thrones Season 2, Episode 5
It could be light bouncing
off a NATURAL object,
The Big Bang Theory Season 12, Episode 20
Also, curry's a NATURAL laxative and
I don't have to tell you that, you know...
The Big Bang Theory Season 1, Episode 1
Primates such as ourselves
have a NATURAL instinct...
The Big Bang Theory Season 4, Episode 19