nowaday,there are lots of problems related with teenagers,that is the result of environment. First of all,family can lead to problem in teenager .For example,teenagers have been very pressure from parents or have been hurt mentally, its causes clinical depression in teenager.Also,The behaviors of parents affect the behavior of teenagers. Secondly,Friends are the most important thing that affect the behavior of teenager,such as, smoking,drinking and nightlife. Finally, Society also influence the behavior of adolescents, such as sexual deviation or Imitation behavioral come from the media such as TV or the internet. In conclusion, the experience of teenager is complicated by a variety of influences that can have both positive and negative effects ,which is result from family, friends and society.