"On duty" -- adverb or adjective?


English - US
"There are a lot of doctors on duty on the first floor."

I am certain "on the first floor" is an adverb in the sentence above, but I am not sure if "on duty" is an adjective or an adverb. If the sentence were rewritten, it would be, "A lot of doctors are on duty today," which would seem to make it adjective phrase, which would make sense given that "are" is a linking verb. The dictionary here says "on duty" means "at work," which would indicate where there doctors are, which would be more like something an adverb would describe.

This one confuses me, even though I teach grammar to ESL students. After looking at the sentence again, I'm wondering if "on the first floor" is an adjective or adverb.

Your help in clearing up these questions would be appreciated.
Last edited:
  • PaulQ

    Senior Member
    English - England
    In "A lot of doctors are on duty today,", I would day that "on duty" is an adpositional phrase acting as the complement. Compare: "The doctors are in the hospital."

    Preposition + noun

    Wait for other opinions.


    Signal Modulation
    English - Scotland
    If you cut it down to "the doctor is on duty" I think it's pretty clear that it's a property of "the doctor" and not of the verb "is". It is therefore an adjective.