_Syntax

Thematic properties

I. Modals, auxiliary have and be, and periphrastic do can appear with any subject, since they do not assign a theta role to the subject (which receives it instead from the main verb in the VP).

II. Auxiliary have and be and periphrastic do should be distinguished from main verb counterparts, which do have thematic structure.
(Note: periphrastic do should not be confused with do so, the proform for V': He didn't do so.)