There are three members in my family:my father,mother and I还

应该用 I
再问： 为何 请从句子结构分析
再答： 很简单，所填写的内容是作为名词在句子中存在的。原句可拆分为：My father is in my family, my mother is in my family, I am in my family, and there are three members in my family. 而me通常是作为宾语时被使用的，如：Our teacher gave some apples to Tom, Jerry, and me.