Copula construction

A. Copula construction

(11) COPULA CONSTRUCTIONS

a. NP Copula AP Fiona is very happy. (COPULA, ASCRIPTIVE)

b. NP Copula NP Fiona is the best student. (COPULA, EQUATIVE)

c.NP Copula PP Fiona is in Auhtermuhty. (COPULA, LOCATIVE)

Ascriptive copula clauses are used to ascribe a property to an entity. In (11a), happiness is ascribed to Fiona. Equative copula clauses are used to state that one entity is identical to another entity. Speakers use (11b) to say, on the assumption that there are two entities Fiona and the best student, that these two entities are one and the same person. Fiona is equated to the best student the label (COPULA, LOCATIVE) is self-explanatory. These constructions are used in order to state where some entity is located.

source: Pak Faizal's E-book of English Syntax - Blog Pak Faizal