Active and Passive Voice: Rules and Transformation Guide

Introduction

Have you ever wondered why some sentences sound direct and strong, while others feel more formal or indirect? The answer often lies in voice — whether a sentence uses the active voice or the passive voice. Understanding these two structures will help you write more clearly, choose the right tone, and improve your overall English grammar. In this guide, we will explain the rules, show you how to transform sentences from active to passive (and vice versa), and give you plenty of practice.

What Is Active and Passive Voice?

Active voice means the subject of the sentence performs the action. For example: The cat chased the mouse. The subject (cat) does the action (chased).

Passive voice means the subject receives the action. For example: The mouse was chased by the cat. The subject (mouse) receives the action (was chased).

Passive voice is formed using the verb “to be” (in the correct tense) + the past participle of the main verb. The doer of the action can be mentioned after “by” or omitted if unknown or unimportant.

Rules for Active and Passive Voice

1. Only transitive verbs (verbs that take an object) can become passive. Intransitive verbs (e.g., sleep, arrive) have no object, so they cannot be changed to passive.
2. The object of the active sentence becomes the subject of the passive sentence. Example: Active: She wrote a letter. → Passive: A letter was written by her.
3. The subject of the active sentence becomes the agent in the passive sentence (introduced by “by”). If the subject is unknown or obvious (e.g., people, someone), it can be omitted.
4. The verb tense must be preserved. Change the form of “to be” to match the original tense, and always use the past participle of the main verb. See the table below for common tense changes.
5. Modal verbs (can, must, should, etc.) are followed by “be” + past participle. Example: Active: You must finish the report. → Passive: The report must be finished.
6. Imperative sentences (commands) form passive with “Let” + object + “be” + past participle. Example: Active: Open the door. → Passive: Let the door be opened.
7. Verbs with two objects (e.g., give, send, offer) can have two passive forms. Example: Active: He gave me a book. → Passive 1: I was given a book. → Passive 2: A book was given to me.

How to Use Active and Passive Voice

Step 1: Identify the tense of the active sentence

Look at the main verb and its form. For example: “She is reading a novel” (present continuous).

Step 2: Move the object to the subject position

Take the direct object (“a novel”) and place it at the beginning of the passive sentence.

Step 3: Add the correct form of “to be”

Match the tense of “to be” to the original tense. For present continuous, use “is being” (singular) or “are being” (plural).

Step 4: Change the main verb to the past participle

For “read,” the past participle is “read” (same spelling, different pronunciation).

Step 5: Add the original subject after “by” (optional)

If you want to mention the doer, add “by her.” If not, omit this part.

Example transformation:
Active: She is reading a novel.
Passive: A novel is being read (by her).

Examples in Sentences

Below are 10+ sentences showing active and passive voice. The grammar point is bolded.

• Active: The chef cooks dinner every evening. Passive: Dinner is cooked by the chef every evening.
• Active: The students finished the project yesterday. Passive: The project was finished by the students yesterday.
• Active: Someone has stolen my wallet. Passive: My wallet has been stolen.
• Active: The committee will announce the winner tomorrow. Passive: The winner will be announced tomorrow.
• Active: The children are playing soccer. Passive: Soccer is being played by the children.
• Active: You can open the window. Passive: The window can be opened.
• Active: The company hired 50 new employees. Passive: 50 new employees were hired.
• Active: The teacher had explained the lesson. Passive: The lesson had been explained by the teacher.
• Active: They are building a new hospital. Passive: A new hospital is being built.
• Active: The dog bit the mailman. Passive: The mailman was bitten by the dog.
• Active: Nobody has seen the thief. Passive: The thief has not been seen.
• Active: She will finish the work by 5 PM. Passive: The work will be finished by 5 PM.

Common Mistakes

Here are four common errors learners make with active and passive voice, with corrections.

• Mistake 1: Forgetting to change the verb tense correctly.
  ❌ The window is broke by the boy.
  ✅ The window was broken by the boy. (Use past participle “broken,” not past simple “broke.”)
• Mistake 2: Using passive with intransitive verbs.
  ❌ The train was arrived by the passengers.
  ✅ The passengers arrived at the station. (“Arrive” has no object, so passive is impossible.)
• Mistake 3: Omitting “by” when the agent is important.
  ❌ The cake was eaten. (If we need to say who ate it.)
  ✅ The cake was eaten by the children.
• Mistake 4: Using the wrong form of “to be” for the tense.
  ❌ The report is written by the team last week.
  ✅ The report was written by the team last week. (Past tense needs “was,” not “is.”)
• Mistake 5: Adding an unnecessary object in passive.
  ❌ The letter was sent it by her.
  ✅ The letter was sent by her. (Remove “it” because the subject is already “the letter.”)

Quick Summary

• Active voice = subject does the action. It is direct and often shorter.
• Passive voice = subject receives the action. It is formed with “to be” + past participle.
• Only transitive verbs (with an object) can become passive.
• To transform active to passive: move the object to subject position, add the correct “to be” form, change the main verb to past participle, and optionally add “by” + the original subject.
• Use passive when the doer is unknown, unimportant, or when you want to emphasize the receiver of the action.

Practice Exercises

Fill in the blanks with the correct passive form of the verb in parentheses.

1. The letters ________ (send) by the secretary yesterday.
2. English ________ (speak) in many countries around the world.
3. The car ________ (repair) right now by the mechanic.
4. All the homework ________ (must / finish) before Friday.
5. A new shopping center ________ (build) in our town next year.

Answers:

1. were sent
2. is spoken
3. is being repaired
4. must be finished
5. will be built

Conclusion

Mastering active and passive voice will make your English more flexible and precise. Use active voice for clear, direct statements, and passive voice when you want to focus on the action or the receiver. Practice the transformation steps regularly, and soon it will become second nature. Keep writing, and don’t be afraid to experiment with both voices in your sentences!

FAQ

1. When should I use passive voice instead of active voice?

Use passive voice when the doer of the action is unknown, unimportant, or obvious from context. For example, in scientific writing, we often write “The experiment was conducted” instead of “We conducted the experiment.” Passive is also useful when you want to emphasize the receiver of the action, such as in news headlines: “The president was elected.”

2. Can every sentence be changed from active to passive?

No. Only sentences with a transitive verb (a verb that takes a direct object) can become passive. Sentences with intransitive verbs like “sleep,” “cry,” “arrive,” or “die” have no object, so they cannot be transformed. For example, “She sleeps” has no object, so there is no passive form.

3. What happens to the verb tense when changing from active to passive?

The tense must stay the same, but the form changes. You replace the main verb with the correct tense of “to be” plus the past participle. For example: active present simple “eats” → passive “is eaten”; active past continuous “was eating” → passive “was being eaten”; active future “will eat” → passive “will be eaten.”

4. Is it always wrong to use passive voice in writing?

No, passive voice is not grammatically wrong. However, overusing it can make writing wordy, vague, or less engaging. Most style guides recommend using active voice for clarity and directness. Use passive voice deliberately when it suits your purpose, such as in formal reports, academic writing, or when the doer is irrelevant.