What in the world are you doing here?
"what/who/why/where/when/how in the world "表示強烈的驚奇
eg: I thought you were in hongkong.What in the world are you doing here? 我以為你在香港呢,我的天你怎么在這兒???
Where in the world did you get that diamond necklace? 誒呀,你這項鏈是在哪兒買的呀???