Because she had no arms. "knock knock" "whose there?" "not sally!"
Stick them up front of the group and tell them to wave their arms!
A Speech Impediment
Because the rain in Spain falls mostly in the plain.
Valleys that have fallen out after an argument.
Nothing, because he is the one who knocks.
Someone who pointlessly knocks on the door.
She had no arms. BONUS JOKE: Knock Knock. Who's there Not Sally.
