Here are the completed sentences:

**Exercise 12: Complete the sentences with a or an.**
1. My sister's husband is **a** chef.
2. Tomato is **a** red vegetable.
3. You've got a cold? Eat **an** orange every day.
4. Cake and ice cream is **an** unhealthy snack.
5. **An** apple is a healthy food.
6. Let's have **a** pizza for lunch.
7. My brother is **a** vegetarian.
8. I have **an** egg for breakfast.

**Exercise 13: Complete the sentences with a, an, or the.**
1. There is **a** new cinema in my town.
2. Cut tomato into pieces. Put pieces in **a** sandwich.
3. Boil **an** egg in some water for three minutes. Carefully, take **the** egg out of **the** boiling water.
4. **An** onion is **a** type of vegetable.
5. Homework for tonight is **the** grammar exercise on page 10.
6. I’ve got **a** great birthday present for my brother. It’s **a** camera.

**Exercise 14: Michelle is at a cooking school in London. Complete her postcard with a, an, the, or no article (O).**
Hi Mum,
Here I am, at (1) **a** cooking school in (2) **London**. It’s great here! I live near the centre and I usually walk to school because (3) **the** traffic is very bad in (4) **the** city centre.
There are four hours of lessons a day! (5) **The** lessons are really fun but also hard work. Today’s lesson is how to cook (6) **an** Italian food-great! I love (7) **O** pasta!
See you again!
Michelle