Abstract: This paper explores how some notional verbs merge into the relative clause structure.It first examines in the light of cognitive grammar how the double predicate expressions are subjected to test by the categorizing structure or sanctioning structure and become categories of varying degrees of complexity, and how the components of these expressions are integrated as complex and schematic symbolic units through the correspondence between the substructures of the components.Then in view of function the paper looks into how the expressions stand to test of language use in various genres and registers and acquire the conventional linguistic unit status, thus becoming part of the full schematic network, and meanwhile the verbs merge into the constuction of \PredAdjSbj be PredAdj\, which is called relative clause for brevity in the title.