Have you ever thought about your body changes? Up to about the age of eight or nine, girls and boys look quite alike. They have similar shaped bodies and their voices sound almost the same. As they grow, all their organs(器官) grow, too.
At the same time after the age of ten, often at eleven or twelve, boys' and girls' bodies start changing. This time of change is called puberty(青春期), The changes mean their bodies are getting ready so that they'll be able to have children when they're older.
The changes don't happen to everyone at the same time. Each person has his or her own body—changing timetable. By the time they're eighteen, they should be complete. Girls start changing some years sooner than boys. Until they're fifteen or so, they grow faster than boys of the same age. As years go by, boys can catch up and grow taller and stronger. Girls grow taller and heavier as well. Their faces and breasts become fuller. As well as all the changes you can see happening, other important changes — ones you can't see — are happening inside your body at the same time.
