Knock knock Who's there? Anna Anna who? Anna partridge in a pear tree! :D

*knock knock* whos there? sir theres been an accident. theres been an accident who?

"Knock knock." "Who's there?" "Doorbell repairman."

Knock knock?? Who's there?? Jehovah Witness. Knock knock?? Knock knock?? Hello?? Knock knock??