It is evening. Vicky's father is going along the corridor to the bathroom. Suddenly he hears his daughter speaking to somebody in the bathroom in a kind voice. He opens the door quietly. Little Vicky is holding a cat in her arms and cleaning its teeth with his tooth-brush. "What does it means, Vicky?" father shouts. "Why are you cleaning the cat's teeth? Cats don't clean teeth!" "But, father, you always say that everybody clean teeth. So we are cleaning our teeth with this tooth-brush every evening"