这个英语句子真不懂?这是新概念 二 的练习题,这里说； I have already had lunch.have yo

这个英语句子真不懂?这是新概念 二 的练习题,这里说； I have already had lunch.have you had ...
这个英语句子真不懂?
这是新概念 二 的练习题,这里说；
I have already had lunch.
have you had lunch yet?
不明白为什么用had lunch?had 不是用在过去完成时态吗?
下面给我个 练习 模仿上面提问,
I have already seen the new play at 'The globe'.
Have you ______________________?
是不要加had 不懂?求救……