1. I / out / friends / love / with / weekend / at / hanging / my / the
=> I love hanging out with my friends at the weekend.
2. Doing / reduce / of / exercise / obesity / physical / helps / risk/ the
=> Doing physical exercise helps reduce the risk of obesity.
3. Social / teenager's / to / important / networks / life / are / a
=> Social networks are important to teenager's life.
4. Reading / most / the / activities / among / teenagers / these / and / crarts / making / books / are / popular
=> Reading books and making crafts are the most popular activites among these teenagers.