Properties of adjuncts/modifiers:
- obligatoriness: modifiers are optional.
- iterability: there can be an arbitrary number of modifiers.
- constancy of semantic contribution: the relation between the modifier and the head is always the same.
- semantic: indicates some further properties of the head.
- the modifier is only compatible with heads of a particular class.
- word order: modifiers are further away from the head than complements
- word order: in English, modifiers can occur on either side of the head (green car in the garage, quickly [talked to Jim] in the hallway)
- 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, complement, specifier
- modifiers in the clause