请问外国人在邮件开口的WHAT'S UP

请问外国人在邮件开口的WHAT'S UP 外国人说what's up怎么回答 两个外国人见面之后打招呼,说“Hey,what's up! 请问 What's up 是What is up 关于what's up我看电影里黑人都是问一句what's up答一句what'up但是实际跟外国人讲的时候他们都是答not much还有什么答法,知道的说一下, what's up的意思 what's UP 的意思 What’s up?的意思 What's up的回答 请问在美国如果有人问候你What's up? 该怎么答? 初次聊天外国人问候what's up的具体回答与外国网友聊天,第一次聊他们都问候what's up,如果我回答not much感觉有点怪,听说还有一种说法是fine之类的,还有直接回what's up,究竟如何?不用说太详细. what's up和what's on的区别?what's up和what's on的区别是什么? hey ,what's up ,buddy?的回答? What's up的同义句 what's up的原唱是谁 what's up是谁唱的, What's up What’s up