The Syntactic Structures of "Jiu" and "Cai" and Their Compatibility with "Le"

By examining the presupposition time of adverb jiu and cai,this paper attempts to find the syntactic conditions of their co-occurrence with the particle le in a stringent laboratory method.The research shows that in jiu sentence the event time lies before the expected time.The event happens out of the speaker's expectation which is newsworthy,so jiu and le are semantically compatible.While in cai sentence the event time lies after the expected time.The event happens in the speaker's waiting,it's not newsworthy,which leads to the incompatibility of cai with sentence-end le.If sentence-end le,suffix le and jiu/cai are regarded as unary prefix operators,in terms of their scopes,the adverb operators jiu/cai can introduce situation variables which are compatible with the suffix le operator.The situation variables introduced by the adverb operators jiu and the sentence-end operator le are semantically compatible,i.e.,no conflict occurs between the realization and after-realization state of the expected event,while the situation variables introduced by the adverb operators cai and the sentence-end operator le are semantically incompatible,i.e.,a conflict occurs between the un-realization and after-realization state of the expected event.