This paper aims to analyze ‘fragmental utterance’ such as “XP가 왜?” and “왜 XP가?”, and reviews the discussions on the question adverbs ‘왜’ and the subject marker ‘-이/가’. By comparing them through the fragmental utterance, it is possible to present doubts about whether ‘왜’ is a sentence adverb. It is also confirmed that the noun phrase with ‘-이/가’ can become the focus, regardless of word order. Multiple fragmentary sentences such as “XP가 왜?” and “왜 XP가?” are created by 'multiple ellipsis' from different sentences, not by 'move-and-delete' from the same sentence.
It is significant that the fragmental utterance is useful for grammatical analysis.