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• Knock, knock." "Who's there?" "Oz." "Oz, who?" "Oz be the new mayor!
• Knock, knock. Who's there? Harry. Harry who? Harry up, I'm hungry!
• Knock, knock. Who's there? Gladys. Gladys who? Gladys Thanksgiving. Aren't you?
• Knock knock Who's there? Little old lady Little old lady who?
  Gee, I didn't know you knew how to yodel....