The sentence you provided is incomplete, and it's not clear what American teens are setting an example for. Could you please provide more context or complete the sentence? Here are a few possible completions based on common contexts:

1. **American teens are setting an example for their peers globally by volunteering in their communities.**
2. **American teens are setting an example for their parents by using technology responsibly.**
3. **American teens are setting an example for future generations by standing up for climate action.**

If none of these fit your intended meaning, please provide more details so I can assist you better.