答案：They had a good time on the Great Wall.

或： They enjoyed themselves on the Great Wall.

解析：have a good time = enjoy oneself 玩得愉快,玩得开心,而且是发生在过去的事情,用过去式.


希望能帮到你,祝更上一层楼O(∩_∩)O
有不明白的请继续追问,可以详谈嘛(*^__^*)