Ответ:
Past Simple
Last summer Billy stayed with his grandma and grandad. They lived near the sea. They had got a dog. Billy swam with the dog and his grandma. His grandad didn't work. He and his grandad played football and rode bikes. Billy went with his grandma and grandad to town. They looked at the shops and had lunch in a restaurant. Then they went to the cinema. Billy loved his summer holiday. He had a great time.
Future Simple
Next summer Billy will stay with his grandma and grandad. They will live near the sea. They will have got a dog. Billy will swim with the dog and his grandma. His grandad won't work. He and his grandad will play football and ride bikes. Billy will go with his grandma and grandad to town. They will look at the shops and have lunch in a restaurant. Then they will go to the cinema. Billy will love his summer holiday. He will have a great time.