Tom goes to see his grandparents with his father. On the train, Tom often puts his head out of the window. His father says, "Tom, don't put your head out of the window. ''But Tom goes on putting his head out of the window.

    His father takes Tom's hat quietly, hides(藏)it behind his back and says to Tom, "You see, your hat is gone(消失)."Tom is afraid. His father says, "Well, whistle once. Maybe your hat will come back. "Tom whistles. His father puts the hat on Tom's head quickly. "Oh! It's wonderful! "Tom laughs and says. He quickly takes his father's hat and throws it out of the window. "Now it's your turn to whistle, Dad!" he says happily.