Properties of complements:
- semantic: entities or locations whose existence is implied by the meaning of the head.
- obligatoriness: complements are usually obligatory.
- iterability: every type of complement can occur only once.
- constancy of semantic contribution: the relation between the head and the complement is determined by the head (semantic role).
- morphological marking: the head determines the syntactic realization of the complements (i.e. how many complements are there? which form do they have?)
- word order: complements are closer to the head than modifiers in English
- word order: in English, complements follow the head
- verb: the pro-VP forms do so/do the same thing can combine with a modifier, but not with a complement.
- noun: the pro-N' form one can combine with a modifier, but not with a complement.
- other grammatical functions: head, modifier, specifier
- complements in the clause: direct object, indirect object, predicative complement, oblique complement