Salesman
A salesman telephone a household, and a four-year-old answered.
Salesman: "May I speak to your mother?"
Child: "She's not here."
Salesman: "Well, is anyone else there?"
Child: "My sister."
Salesman: "O.K., fine. May I speak to her?"
Child: "I guess so."
There was a long silence on the other phone. Then;
Child: "Hello?"
Salesman: "It's you. I thought you were going to call your sister."
Child: "I did. The trouble is: I can't get her out of the playpen."