Sure! Here are the correct answers for the sentences:

1. **D. at**
2. **A. for walks**
3. **C. taking**
4. **B. gets up**
5. **B. walks**
6. **D. doing**
7. **C. sees**
8. **A. travels**

So the completed sentences would look like this:

What do you like doing best (1) **at** your spare time? My cousin Henry likes going (2) **for walks** in the country and (3) **taking** photos. Sometimes he (4) **gets up** with his friends, and they (5) **walk** at the park or at the beach. They always (6) **do** a good time. His brother Chris isn’t (7) **seeing** on walking. He spends most of the (8) **travels** at home.