Here are the sentences completed with the appropriate forms of the verbs in parentheses:

11. We **are picking** used bottles and paper to recycle at the moment. (pick)
12. My classmate and I often **clean** our neighborhood at the weekend. (clean)
13. How about **reusing** the plastic bottle to grow flowers? (reuse)
14. If she turns off the lights, she **will save** the electricity. (save)
15. **Did** you **take** part in the environment project last week? (take)