This text put forward a framework of ＂P （x,y 又）, Q＂ causal construction, where the mark isn＇t as obvious as other constructions and give an in-depth discussion of its＇ syntactical-semantic constraints and restriction mechanism in discourses. Syntactically, it behaves a certain type of Gestalt and n＋1 （n〉2） is the prototype. Semantically, the construction is constrainted by the logical basis, conjunctional marks, expression way and ellipsis. Pragmatically the first performance of the discourse constraints behaves in different order, w...
