Because she has no arms. Knock Knock. Who's there Not Sandra.
Me: why Him: Timmy has no arms. Knock knock. Me: Who's there Him: Not Timmy.
Jimmy pushed her... Which is a shame because she was getting used to swinging without arms.
Why did Sally fall off the swing? Because she didn't have any arms. Knock Knock. Who's there? Definitely not Sally. Why did Jimmy drop his ice cream? He was hit by a truck Why didn't the truck turn out of the way? Sally Was driving
Instead of 'knock knock', they say, 'Arrr you there !'