Here are the sentences completed with the past simple form of the verbs:

1. **donated** your used books to your local library or charities.
2. **organized** a fundraising event to raise money for charity.
3. **polluted** rivers and lakes.
4. **planted** trees or flowers in your backyard or community garden.
5. **volunteered** at a nursing home, soup kitchen, or homeless shelter.
6. **recycled** plastic and paper for a clean environment.
7. **provided** nutritious meals to the poor and needy people.
8. **tutored** homeless children who were unable to attend school.