9.2 Active and Passive Voice

Active and passive voice shape how you express actions in sentences. Active voice puts the doer first, making writing clear and direct. Passive voice flips this around, emphasizing the receiver of the action or the action itself. Knowing when to use each voice is a real skill, and it comes up constantly in both everyday and formal writing.

Sentence Structure

Active and Passive Voice Fundamentals

In active voice, the subject performs the action. In passive voice, the subject receives the action. That single difference changes the entire feel of a sentence.

• Active: The dog chased the cat. (The subject, "dog," is doing the chasing.)
• Passive: The cat was chased by the dog. (The subject, "cat," is receiving the action.)

The subject-verb relationship is what determines voice. In active sentences, the subject acts. In passive sentences, the subject is acted upon. The object in an active sentence (the thing receiving the action) becomes the subject when you rewrite it in passive voice.

Characteristics of Active and Passive Sentences

Active voice follows a straightforward pattern: Subject + Verb + Object. This structure tends to produce sentences that feel direct and concise.

Passive voice reverses that flow: Object (now subject) + "to be" verb + Past Participle + (optional) "by" + Agent. This structure shifts attention away from the doer and toward the action or its recipient.

Neither voice is inherently "better." Active voice is usually preferred for clarity, but passive voice has real uses, especially when the doer is unknown, unimportant, or when you want to keep the focus on the action itself.

Passive Voice Components

Elements of Passive Construction

Every passive sentence requires two things: a form of "to be" (is, am, are, was, were, been, being) plus a past participle (the verb form that typically ends in -ed, -en, -t, or has an irregular form like written or broken).

• The letter was written by Maria. ("Was" = form of "to be"; "written" = past participle.)
• The results are being analyzed. ("Are being" = form of "to be"; "analyzed" = past participle.)

The agent is the doer of the action, introduced by a "by" phrase. But here's something worth remembering: the agent can be dropped entirely when it's unknown, obvious, or unimportant.

• The window was broken. (We don't know who did it, so no agent is needed.)
• Mistakes were made. (The agent is deliberately left out.)

Identifying and Using Passive Voice

To spot passive voice, look for the combination of a "to be" verb + past participle. Common auxiliary verb combinations include is, was, were, has been, will be, is being, and had been.

Passive voice creates a more formal or objective tone, which is why it shows up frequently in scientific writing (The solution was heated to 100°C) and official reports (The suspect was apprehended at noon). In both cases, the focus is on what happened rather than who did it.

Voice Conversion

Transforming Active to Passive Voice

Use these steps to convert an active sentence to passive:

1. Identify the subject, verb, and object in the active sentence.
2. Move the object to the beginning of the sentence; it becomes the new subject.
3. Change the verb to a past participle and add the appropriate form of "to be" (matching the original tense).
4. Add "by" before the original subject (now the agent), if you want to include it.
5. Drop the agent if it's unnecessary or unknown.

Transforming Passive to Active Voice

To go the other direction, from passive back to active:

1. Find the agent (usually in a "by" phrase). This becomes your new subject.
2. Place the agent at the beginning of the sentence.
3. Remove the "to be" helper verb and convert the past participle back to the appropriate tense of the main verb.
4. Move the passive subject to the end as the object.
5. If no agent is stated, supply a logical one or use a general subject like "someone" or "researchers."