The key answer of exercise 3

a)

1. In any reason
2. At first
3. One day I was there
4. One of my favourite places
5. The part of the forest
6. The main reason that the forest is one of my favourite places

b)

One of my favourite places is my grandmother's house. The part of the house which I like best is the garden. The main reason why I like it there is because there are lots of really big trees. In any season, it is a relaxing place to be, but I especially like it in the summer. The last time I was there, we had a lovely picnic sitting under the trees.