The party was horrible: the guests were all talking about things that had nothing to do with me.

had 是动词 have 的过去式，表示"拥有"或"与...有关"。 nothing 是代词，表示"没有任何东西"或"无关的事情"。 to 是介词，在这里用于连接动词短语。 do 是动词，表示"做"或"与...相关"。 with 是介词，表示"和...一起"或"关于..."。 had nothing to do with 是一个固定短语，意思是"与...无关"或"和...没有关系"。