Passives

In passives the subject of active voice becomes the agent and the object of active voice becomes the subject. In addition, the verb phrase has an extra be-verb. The agent of passive voice is often deleted. Let's look at a few examples:

Mrs. White scolded Mrs. Black.

In this example the subject is Mrs. White and the object is Mrs. Black. Let's passivize the sentence:

Mrs. Black was scolded by Mrs. White.

Now the object of the first sentence is the subject and the subject of the first sentence is the agent. The agent is found in a prepositional phrase with the word by.

We can say that the subject of active voice is demoted to agent in passive voice. Likewise, we can say that the object of active voice is promoted to subject in passive voice.

Here's another example:

William Shakespeare wrote Romeo and Juliet.
Romeo and Juliet was written by William Shakespeare.

Here William Shakespeare is the subject of active voice and the agent of passive voice. Romeo and Juliet is the object of active voice and the subject of passive voice.

This is our last example:

He is painting the house brown.
The house is being painted brown.

In this case the agent of passive voice isn't expressed. We see the object of active voice (the house), which is the subject of passive voice. In active voice we have a present continuous verb, and in passive voice we have a present continuous passive which adds a be-verb to the verb phrase.

Passives have a subject and agent, but the agent is often deleted. In passives the subject of active voice assumes object position and the object of active voice assumes subject position. With respect to verbs, passives have one more be-verb.