Sure! Here are the answers based on the passage provided:

9. **How much TV do children in the United States watch on an average day?**
- Children in the United States watch an average of three to four hours of television a day.

10. **What are the good effects of television on children?**
- Television can entertain, inform, and keep children company. It can also provide educational content through suitable programs.

11. **What may be the bad effects of watching too much TV on school work?**
- Excessive television watching can take time away from important activities such as reading, homework, exercise, and family interaction, which may lead to lower grades and other issues.

12. **Should parents let their children watch TV for a long time?**
- No, parents should not allow children to watch long blocks of TV.

13. **Which programs are appropriate for children and which are not?**
- Children's shows on public TV are appropriate, while soap operas, adult sitcoms, and adult talk shows are not.

14. **What can parents do to limit their child's screen time?**
- Parents can avoid allowing long blocks of TV, help choose suitable programs, set certain periods when the TV will be off, and encourage children to engage in other activities like reading or exercising.