Abstract: “WhenX” is a common structure in Chinese for time positioning,usually reveals the subsequent events happening,ongoing,end of time in subsequent sentence.The structure is very inclusive,X is very complicated and often not only contain one predicate core,and the cores may have multiple logical semantic relationships.“WhenX” can be called the coherent core type when contains coherent cores.According to the core verbs in X having or not having a common subject,it can be divided into common layers and multi-core “whenX” and different layers and multi-core “whenX”.And according to cores in X have or not have space,with or without markers,it can be divided into four types,covering coherent complex sentences and coherent verb sentences.Coherent core type “whenX” has special expression function:to reveal the time of subsequent sentence,and with a strong narrative.This structure in discourse may help to keep coherence and highlight focus.

Key words: coherent core type, when X, core predicate, coherent complex sentences, coherent verb sentences