Abstract: (Ni) yisi (shi) +X (literally "(you) mean (be) + X") occurring at different sequential positions may execute various social actions. This research adopts conversation analysis as its research methodology and probes into "(ni) yisi (shi) +X" as the third turn in the questioning/answering sequence. Data analyses prove that "(ni) yisi (shi) +X" at this sequential position displays the questioner's difficulty in understanding the answer, thus the questioner initiates a repair with "(ni) yisi (shi) +X" to provide the answerer with an opportunity to confirm, disconfirm the questioner's candidate understanding or even to further provide more relevant details. Our conclusion is that "(ni) yisi (shi) +X" shows the questioner's local analysis of the answer and displays the questioner's difficulty in understanding. The overall sequence organization manifests the questioner and answerer's mutual orientation to the moment-by-moment unfolding of a conversation and their mutual efforts to achieve intersubjectivity in talk-in-interaction.