They're all wrong. You can't translate these sentences in Chinese like that, it's too direct. You've gotta look at the culture, first. It's very common to say shit or damn on TV, now-a-days, in America at least, but in China, you can't say bad words. There's rarely a situation. What's happening - If you mean by what's up like what's going on, you could say 怎么样? I think it's better to say 咋了? (Dongbei dialect) What the hell - think about what little kids say, or should say actually, they're not supposed to say hell. So Chinese would say, 我搞不定, I can't understand what the problem is. Seriously - 真的吗！？ This is really lame - 真无聊 should be more of a boring kind of thing, not lame What's up little man - 小朋友，你怎么样？They call little kids small friends, not little man. Little man, in Chinese, may be referred to your penis. I figured that out in kind of the hard way. They call their older sisters 姐姐, or if really old 大姐, and so I thought it would be 小弟弟, but that actually means your dick. It's kind of really hard for me to translate these, because you never hear direct translations cause culture is so different. When I read what the Chinese people write, it doesn't make sense when I translate it to fit the meaning of what it is in English.

* whats happening? (like 怎么了?or 发生什么事?) * what the hell !? (mad. someone made annoying mistake) 去他的！or 这是怎么了? * You're killing me ! (not happy about this, but I'll do it) 你杀了我吧！ "吧"it Key words. * Seriously! (like "You've got to be kidding me"!) 认真地！I think it difficulty for chinese ! * Oh My God! (OMG!) 噢,我的天啊！or 噢,我的上帝!It useless in the chinese!so their are speak chinese-english too ! * This is (really) Lame! (social setting. 真无聊!or 太僵化了!or 太无聊了!or 没劲! * whats up little man (hello to a child) 小男子汉，如何？

* whats happening? 什么情况？ * what the hell !? (mad. someone made annoying mistake) 我勒个去 * You're killing me ! (not happy about this, but I'll do it) 烦死了 * Seriously! (like "You've got to be kidding me"!) 真的假的 * Oh My God! (OMG!) 天哪！/ 我勒个去！/ 我了个亲娘四舅姥姥！ * This is (really) Lame! 太傻X了 * whats up little man (hello to a child) 小盆友，真可爱，爱吃萝卜爱吃菜

The first one should be "怎麼了?" If we translate the second one (what the hell !? ) into Chinese, it makes little sense For "seriously" and "Oh my god", they are translated really well!

* whats happening? (like 怎么样) 什么事？，发生什么事了？ * what the hell !? (mad. someone made annoying mistake) 什么是地狱！搞什么？怎么搞的？是口头语，表示不太满意。 * You're killing me ! (not happy about this, but I'll do it) 你杀了我！你杀了我吧！口头语，表示别人让你做的事情出乎你的意料，觉得不太可能做的，就是你让我做这个，不如杀了我吧，不是真的杀。 * Seriously! (like "You've got to be kidding me"!) 认真地！认真点！ 严肃点！表明这是很严肃的，不是开玩笑的。 * Oh My God! (OMG!) 我的天啊！哦，天啊！表示很吃惊，感到意外，有好的喜欢看到的情况，也可以是坏的不愿意看到的情况发生。 * This is (really) Lame! (social setting. 这是真跛脚 这是站不住脚的，这是差劲的，这是没有说服力的，表明不满意这种表现。 * whats up little man (hello to a child) 小男人，怎么样？怎么样小鬼？怎么样小家伙？一种打招呼 *Whatever! 随便，一种很随意的回答 *Guess what？你知道吗，中国人常用的一句话。 *You know！你知道吧，我说的你知道吧。 *All right, 好吧，就这样吧， *Hopefully! 希望如此吧，