给定一篇文章，将其中的所有代词替换为其对应的具体名词。
下面是一篇示例文章，用于测试代词替换功能：

John and Jane went to the park. He had fun riding his bike, and she enjoyed reading a book. Later, they had a picnic and ate sandwiches. They had a great time.
John and Jane went to the park. John had fun riding his bike, and Jane enjoyed reading a book. Later, John and Jane had a picnic and ate sandwiches. John and Jane had a great time.