nFunction of constituents wrt basic position
nAssignment
nVerbs assign theta-roles to arguments
nPrepositions assign theta-roles to objects
nRole played by each NP in a sentence
nAgent: entity that performs an action
nTheme, Patient: entity that undergoes an action
nSource, Goal, Location, Path, Instrument
nExperiencer: perceiver of a cognitive stimulus
nStimulus: perceived cognitive stimulus
nVarious theories, various roles