In the eyes of parents, the former children may be smart, excellent in study and good-behaved, but when they arrive at the university, they seem to have suddenly changed, pretending, dressing up and following the fashion, often coming home late at ordinary times, and even failing the final exam.

According to the traditional definition of adolescence, junior high school begins at the age of 12 to 13 and ends at the age of 18, so the calculation time of adolescence is six to seven years. However, today's medicine confirms that puberty actually started two to three years earlier, that is, about ten years old, but the psychological maturity was delayed by six to seven years, that is to say, girls were twenty-four years old and boys were twenty-five years old, so adolescence lasted for ten to fifteen years, which parents should pay attention to now.