Here are some suggestions to fill in the blanks:

1. **hanging out**
2. **interests**
3. **a musical instrument**
4. **Doing**
5. **sports**

So the completed text would read:

Swedish teenagers enjoy listening to music and **hanging out** with friends, just like most children around the world. Everyone is encouraged to develop his or her own **interests**. Singing and playing **a musical instrument** are popular leisure activities. According to a government website, almost one in three Swedish children aged 13-15 play an instrument in their spare time. **Doing** sports is also encouraged. 68 per cent of 13- to 15-year-olds are members of a sports club. Football is the most popular **sport** among both girls and boys. Then comes horse riding for girls. Boys prefer football, swimming, and ice hockey.