The latest development of Construction Grammar is its extension into the diachronic dimension. Constructionalization concerns drastic changes in the original construction during the emergence of a new creation. Constructional changes refer to modulations of an existing construction and yet play a significant role before and after constructionalization. The two mechanisms are causally related: the accumulated minor changes in the existing construction give rise to major changes， making a new construction emerge. Constuctionalization is involved in multi-dimensional changes in interaction among pragmatic requirement， schematization， thematic roles and semantics-to-syntax linking. The following criteria are used to judge the conditions under which Construction A （an argument structure construction） is divided in two and Construction B is created: （1） the primary prominent conceptual entity in the original construction shifts， （2） the meta-language and constructional meaning vary， （3） the thematic role of the subject slot in Construction A and B differs， （4） the frequency of Construction B is remarkable， （5） the syntactic distribution of the two constructions differs． This study， based on the above criteria， conducts synchronic and diachronic surveys on two divided Chinese mono-transitive constructions with the verb Kao （to test）， instantiated by the sentences Zhangsan Kao Lisi and Lisi Kao TOEFL （literally translated into English as John test Tom and Tom test TOEFL）. The results show that the tester in the subject slot in the basic construction is replaced by the testee and the thematic role is altered in the object slot， and that causes constructionalization eventually to emerge. In the schema， it is the change in the energy source and transmission direction that causes major changes in energy value and results in construction division and re-creation. By contrast， selection of a particular transmission terminal does not cause similar drastic change. Therefore， variation in thematic roles in the subject position causes constructionalization， and that in the object position constructional changes. However， the diversity of thematic roles in the object slot can enhance the frequency and productivity of the construction re-created， making it entrenched to a greater degree. Our survey of a modern Chinese corpus proves that the frequency of the testee-as-subject construction outnumbers that of the tester-as-subject one and shows its greater productivity. In addition， the two constructions in the super-construction network are related to different constructions and thus situated in interactive tension and complementary distribution. Our diachronic survey proves that this particular constructionalization did not occur instantly. The contrastive analysis shows that there is only the tester-as-subject mono-transitive construction in English with no testee-as-subject one in the same syntactic form. This contrast can be accounted for by the topic-prominent and pragmatics-dominant typological features of the Chinese language． Construction Grammar attaches great importance to the sign's form-function pairing and its holistic effect. It also has been promoting the usage-based approach， with the view that a construction can vary in its frequent use in communication. Currently， its diachronic probe into a construction can shed much more light on the interaction among pragmatics， cognition， semantics and syntax in its evolution process. These merits display its creativeness and insightfulness．