Sometimes teachers explain verbs by saying that verbs “describe actions.”
Most verbs do describe actions. For example: run, go, stop, explain, succeed, tell, say, etc.
But not all verbs describe an action. For example, the verb was does not describe any action.
Was is a form that belongs to a verb we all use thousands of times a day: to be.
To be is an irregular verb that has several forms: am, is, are, was, were, being, and been.
Sometimes these verbs are used by themselves in response to something that has gone before. For example:
Who is the best soccer player in the room?
Who was the greatest English monarch?
King Alfred was.
Who’s riding with me?
Ben and Lamont are.
Most of the time, however, verbs like the to be forms must be followed by another word in order to make sense. It wouldn’t be enough, for example, to say “King Alfred was” if nothing has gone before to explain what is meant. We have to say “King Alfred was [something]”:
King Alfred was an admirable leader. (complement)
King Alfred was often ill. (complement)
Words that complete the meaning of verbs that do not describe actions are called complements. At first glance, they may seem to be direct objects. They are not direct objects because they do not receive any action. They simply refer back to the subject of the verb they follow.
Verbs that do not convey an action, but which need another word to complete them are called “being verbs.” A clause that contains a being verb can be turned around and still mean the same thing:
King Alfred was a good leader.
A good leader was King Alfred.
King Alfred was ill.
Ill was King Alfred.
Words used as complements are nouns, pronouns, and adjectives. A complement usually follows the verb.
You’ll find more about being verbs and complements on this site, but further information can wait until you have learned to recognize complements used with the verb to be.