I have never met him before.为什么用met而不是meet

I have never met him before.为什么用met而不是meet I have never met him before中的have是什么意思,为什么没有变过去失态 哪个对为什么? 谢谢 I have met him two days ( before ) I have met him Have you met him?Yes,I have just met him.I had never met him I have never met Carl before ,nor have I heard of him 新概念I had never met him before的意思是什么? I have never met earthquake. you have never met each other before,( i dont think we have met before 中为什么不用had met I had never met him before although I had often heard people have never met还是never have met? I wish _____ him at the party last night A.meet B.met C.have