Because she didn't have any arms. Knock knock. (Who's there?)...not Sarah.
It was too tired
He ran out of balance
Swing!
Because she had no arms. Knock Knock Who's there? Not Sally
No, cows go moo.
I didn't know you could yodel!
Because I've met herbivore.
Because she had no arms. Knock-knock! "Who's there " Not Sarah.