Billy and Bobby were small boys. They were brothers, and they often fought with each other.
Last Saturday, their mother said to them, "I'm going to cook our lunch now. Go out and play in the garden and be good."
"Yes, Mummy," the two boys answered, and they went out.
They played in the garden for half an hour, and then Billy ran into the kitchen. "Mummy," he said, "Bobby's broken a window in Mrs. Allen's house." Mrs. Allen was one of their neighbors.
"He's a bad boy," his mother said. "How did he break it?"
"I threw a stone at him," Billy answered, "and he quickly ducked."