Literally "what" can mean "무엇or 뭐", but sometimes it also can be used as "왜" or "어떻게" because it's more natural. This is happening because of the different sentence structure between Korean and English, I think. For example, What makes you think so? literally...무엇이 당신으로 하여금 그렇게 생각하게 하죠?(sounds quite odd^^/) We rather say.."[왜] 그렇게 생각하죠?" What's the hurry? literally...무엇이 서두름입니까?(Nobody would say like this) It should be "[왜 그렇게] 서두르세요?" What do you think of my new car? 내 새 차 [어떻게] 생각해? What would you have done? 당신이라면 [어떻게] 했겠어요? quite interesting, isn't it.^^/ \^o^/

i think you would better to get some ex to explain that situation.