TV series example of the word

The Big Bang Theory Season 7, Episode 6
I discovered a secret ingredient:

The Big Bang Theory Season 5, Episode 1
and I'll teach you my secret language, Op.

The Big Bang Theory Season 2, Episode 1
What secret? Tell me the secret.

Breaking Bad Season 5, Episode 12
had been keeping a secret from you and Hank,

The Big Bang Theory Season 9, Episode 20
Never have I ever kept a secret bank account