I have my lunch.這句話是不對的.不過在有些語境下也可以使用.比如
同學問你：
Do you want to go for lunch together?
你回答說：
I have my lunch.意思就是你帶了午飯了.
I have had = I have done
I have done something 相信你也懂了吧 就是我完成了什么事
我已經(jīng)吃過午飯了 I have had my lunch.
However,我基本沒聽人這么說過.一般會用在對話中起到強調(diào)的作用.
比如大家在討論一本書,你說
I have read the book.
就是你已經(jīng)讀過這本書了,強調(diào)這個已經(jīng)完成的狀態(tài).