This dissertation examines how the aspectual properties of aspect markers in Mandarin affect the temporal relations between clauses. The significant point (SigP) analysis is proposed to account for the aspectual properties of aspect markers. The SigP for an event/eventuality is defeasibly inferred from the situation types of that event/eventuality. The SigP for accomplishment and achievement is their natural final endpoint. Accomplishment differs from achievement in that the former has a noticeable process between its initial endpoint and its natural final endpoint, while the initial endpoint and the natural final endpoint of the latter coincide. The SigP for activity is undefined because it does not have a natural final endpoint. The SigP for the kind of state with an initial endpoint is its initial endpoint while the SigP for the kind of state without an initial endpoint is undefined.