Spayed means a female dog has had her reproductive organs (ovaries and uterus) removed. Neutered means technically that an animal has been de-sexed, but usually is used to refer to a male dog being castrated.
A complement is a word or word group. that completes the meaning of a. verb. Every sentence has a subject. and a verb. Sometimes the subject. and the verb can express a. complete thought all by themselves.
Confusing direct objects with subject complements. It is easy to mistake a direct object for a subject complement. By definition, a subject complement is a clause or phrase that follows a linking verb, such as is, are or was, and complements, or completes, the subject of a sentence by describing or renaming it.