Question

有没有人说i had have lunch 或者是 i have have lunch ?

为什么有人说I have had lunch , 却不说i had have lunch 或者 i have have lunch ？然后 i had had lunch 和 I have had lunch 有什么区别吗？

Answer 1

为什么有人说I have had lunch? It is because it is a common correct expression.

却不说i had have lunch 或者 i have have lunch ？因为是错误的。It is because they are wrong and not acceptable.

English is not as flexible as Chinese.
我吃过饭了。
=饭我吃过了。=饭, 我吃过了
=吃过饭了,我.
But you cannot say: 饭吃我过了, or 饭吃过我了.为什么却不这样说? It is because it is wrong. No one say so!因为是错误的。

然后 i had had lunch 和 I have had lunch 有什么区别吗？

Yes. There are differences.
I had had lunch. It is used in the past time. The good example is if the person is already dead, the sentence he said when he lived, I have had lunch should be : He said he had had lunch.

I have had lunch. Means you have just finished your meal and you are not hungry any more.