一个美国人问你"what's up"时候应该怎么回答?还是不回答

一个美国人问你what's up时候应该怎么回答?还是不回答 如果有美国人问你what's up?你该怎么回答? 如果对方问你“what's up?”能不能回答terrible 如果别人问你what's up/what's going on 这类打招呼的话你需不需要回答?怎么回答? 打电话的时候 会说what`s up?打电话的时候 说what`s up? 对方问你“what's up?（打招呼,问好）”能不能回答not so good? 如果有人打招呼（注意是打招呼的时候）问what's up 我要怎么回答? 美国人喜欢说的话像what the hell what's up have a good day 一样的短语发几个? 美国人打招呼的What's up,What's happening,How are you doing,What's going on,之类的怎么回答啊? What's up 怎么回答- -要是有人对你说What's up 应该怎么回答?没问你啥意思啊我等知道啥意思就问你咋回答……告诉我我追加分…… What's up What’s up WHAT 'S UP What‘s up what's up man what s up what's up with what's up是什么意思?