Select "a" or "an"

1. My parents have got
   [a|an]
   big house.
2. Your sister doesn't have
   [a|an] atlas with her.
3. Your homework isn't difficult, but you need
   [a|an] ruler.
4. Let's go to the park! I will take
   [a|an] ball with me.
5. Do you like
   [a|an] apple?
6. How often do you read books? I want to give you
   [a|an] interesting one.
7. Her dress is very beautiful. She has
   [a|an] new pair of shoes too.
8. I'd like to buy
   [a|an] new laptop.
9. Are you
   [a|an] honest person? Can I trust you?
10. Can you see
    [a|an] red car across the street?