Mandarin relative clauses (RCs) are head-final constructions that form gap-filler dependencies, whose resolution may differ from filler-gap dependencies. We conducted two eye-tracking experiments investigating native speakers’ reading patterns of Mandarin adjunct relative clauses (ARCs) and possessive relative clauses (PRCs). Experiment 1 compared ARCs with PRCs, revealing that readers found PRCs easier to process, indicating that the explicitly identifiable position of the presumed gap in PRCs facilitates processing. Experiment 2 focused on subtypes of PRCs with alienable versus inalienable possessive relations. The results suggest that inalienability helps resolve gap-filler dependency. Notably, these effects appeared only in late eye-tracking measures, implying that when processing PRCs with a possessum–possessor word order, readers do not predict the possessor for the possessum but wait until they encounter the head noun. Integrating the findings from Experiments 1 and 2, we conclude that in both gapped and gapless RCs, the challenges of semantic resolution significantly affect sentence comprehension.
