注意：How do you do?不是问题，意思是“你好”， How are you?是问题“你
好吗？”，两者不同。What's up? “发生了什么事？”或“情况如何？”= What's happening?和How are you?类似的还有How are you doing?How are things going on?
how are you 是问你好吗，而what's up是看别人和平常有不对有“发生什么是了吗”的意思类似的问候语：Is everything going wellhow do you doall right ?Niceto meet you /nice to see you /glad to see you
