Here are the appropriate articles filled in for the exercise:

1. My mother is **a** doctor and my father is **an** author.
2. Mt. Hood is **a** volcano in Oregon. It's **a** very beautiful mountain.
3. Do you have **a** vacuum? I dropped **a** piece of cake, and I need to clean it up.
4. Do you have **a** dictionary? I don't have one, and I need to look up **a** word.
5. Do you have **a** passport? You need **a** passport to travel outside of the country.
6. Do you have **a** computer? I have **a** laptop and **an** iPad.
7. A: What's wrong? - B: I have **a** bad headache.
8. A: What does he do? - B: He's **an** engineer.
9. A: What did Tom buy? - B: He bought **a** new camera.
10. A: How long does it take to get there? - B: It takes about **an** hour.
11. A: Why can't Shelly travel? - B: She doesn't have **a** passport.
12. A: Where does Barbara live? - B: In **an** apartment on 5th Avenue.
13. A: I don't understand what this word means. - B: You need to buy **a** dictionary.
14. He's a much fitter person than I am; he jogs at least five times **a** week.
15. That brand of organic coffee costs **$85 a** pound!