Conceptually (see also The Fundamental Relations of Syntax and Conceptual Structure) the head of each sentence is a predicate. The predicate combined with its arguments to form a basic eventuality.

(12) Who did John give what to? Both examples have similar argument structures, except for one feature: (13) WH Pol C S T ... V SOMETHING+[+WH\___] SOMEBODY+[-WH\___] (14) WH Pol C S T ... V ...