I don't have a samll nose 为什么要加don't

i don't have any friends为什么要加s i don't have a 为什么英语要加one?列如：I don't have one,为什么要加one? I don\'t have I don't have I don't have a partner to practice English with.请问此处为什么加with 请问〔I don't have a mouth〕中间为什么要加〔a〕啊? don't have a seat为什么要用don't而不用doesn't I don't have a soccer ball. I don't have a web I don't even have a 为什么都说I don't have a shirt而不说I haven't a shirt