I am having trouble understanding how to decide between -는지 and -냐고 in indirect questions. I was trying to translate the following sentence: "I asked him why he had chosen that gift." My translation: 저는 그에게 왜 그 선물을 선텍했었느냐고 물어봤습니다. My Korean friend corrected this to 저는 그에게 왜 그 선물을 선텍했는지 물어봤습니다, but he can't explain why. Can anyone explain the difference to me? 감사합니다!