Question

4) After Scandinavian became Christians, they continued (burn) Yule logs. 5) The custom of (burn) Yule logs at Christmas spread throughout Europe, including England

Answer 1

4) to burn

5) burning

Answer 2

4. After the Scandinavians became Christians, they continued to burn Yule logs.
5. The custom of burning Yule logs at Christmas spread throughout Europe, including England.