Agent Complement – Concept, how to identify it, and examples

We explain what the agent complement is in grammar and syntax, how to identify it and examples in sentences.

agent complement
The agent complement is key in passive voice sentences.

What is the agent complement?

In grammar and syntax, the syntactic function that in a passive voice sentence it exercises a prepositional phrase, and that consists of being the entity that executes the action of the verb. We must not confuse it with the patient subject, who is the one on whom the action carried out falls.

The agent complement is a key part of passive voice sentences, and in Spanish, for example, is always preceded by the preposition “by” (and to a lesser extent, especially in ancient texts, by the preposition “of”). Thus, for example, in the passive sentence “The trees were planted by the neighbors”, we know that those who planted the trees were the neighbors, so “by the neighbors” is the agent complement.

In Spanish, passive sentences are common, and the agent complement does not always appear in them; This is the case, for example, of synthetic or reflex passives, such as “this land is sold”.

How to identify the agent complement?

To identify the agent complement in a passive sentence, it is enough to attend, as we have already said, to who performs the action of the verb in the sentence and in the presence of the preposition “por”. These are key clues in any passive sentence. However, in cases of confusion, it is possible to apply one of the following strategies:

  • Asking “by whom?” or “why?” to the verb. The answer to these questions would have to indicate the agent complement, for example, in the sentence of the previous example, we must ask “By whom were the trees planted?” (answer: “by the neighbors”).
  • Transform the sentence to active voice. Another way to verify the agent complement is to transform the sentence from the passive voice to the active voice, noting that the agent complement will become the subject of the sentence (agent subject). Thus, our example sentence would become “The neighbors planted the trees” (subject: “The neighbors”, verb: “planted”, direct object: “the trees”).

Agent complement examples

Here are some passive voice sentences in which we have highlighted the agent complement:

  • My brother is very dear for the whole family.
  • DaVinci was admired all over the world in his time.
  • Where were the detainees taken For the police?
  • The whole city was traversed by the entourage of the party.
  • Is that song performed for your cousin’s band?
  • The flock was led to the corral by the shepherd boy.
  • The invitations were sent by the organizers from the party.
  • The case will be investigated by Sherlock Holmes.
  • Will those envelopes be classified by machine or manually?
  • The match is being refereed by a true professional.
  • His books were corrected by the same publisher.
  • The one who fears many, of many it is feared.