What in the world are you doing here?
"what/who/why/where/when/how in the world "表示强烈的惊奇
eg: I thought you were in hongkong.What in the world are you doing here? 我以为你在香港呢,我的天你怎么在这儿???
Where in the world did you get that diamond necklace? 诶呀,你这项链是在哪儿买的呀???
