The following discussion took place between a father and his nine-year-old son.

    “It's unfair, Dad. Mum wants me to make my bed, but I don't know how.”

    “It's time for you to learn. Where are you clean sheets?”

    “I don't know.”

    “What so you mean you don't know? You need to take care of your things.”

    “Where are Jack's sheets?” the father called to his wife.

    “Right next to ours.” the wife answered. After a moment, the father asked slowly “Where are ours?”