Here are the corrections for each sentence:

1. **We walked out of the door, down the steps and across the street.**

2. **She loves singing, dancing, and playing the piano.**

3. **The wind moaned, shrieked, and howled.**

4. **The music was fast, brilliant, and exciting.**

5. **He proposes to borrow money, open a store, and go into business.**

6. **The town boasts four libraries, two theaters, and many schools.**

7. **The clouds were thick, black, and threatening.**

8. **He likes running, jumping, and riding a bicycle.**

9. **They worked carefully, quickly, and quietly.**