Complete the sentences with the correct form of the verbs in parentheses. In which sentences are the gerunds used as subjects?

1. ____ (walk) for exercise is better than _____ (run).

2. We should always avoid ____ (stay) up late.

3. _____ (get) enough sleep is as beneficial as ____ (get) enough exercise.

4. Everyone should learn about the importance of ____ (eat) healthy food.

5. People are more interested in _____ (keep) fit these days.

6. The doctor emphasizes _____ (drink) plenty of water every day.