Active & Passive Voice

Every sentence has a voice. The voice tells us whether the subject of the sentence does the action or receives the action. Learning to recognise active and passive voice helps you understand how sentences are built.

What You'll Learn

How to tell whether a sentence is in the active voice or the passive voice
What the basic pattern of a passive sentence looks like
How to change simple active sentences into passive sentences in the present tense and the past tense
How to choose the correct form of "be" (is, are, was, were) in passive sentences

When to Use

Active voice — when the doer is important: "The chef cooked the meal." (We want to know who cooked.)
Passive voice — when the action matters more: "The meal was cooked by the chef." (We care about the meal.)
Passive voice — when the doer is unknown: "My bicycle was stolen yesterday." (We do not know who took it.)
Passive voice — when the doer is obvious: "The thief was arrested last night." (It is clear that the police did it.)

How to Form

Active Voice

In an active sentence, the subject performs the action on the object.

Subject + Verb + Object

"The dog chases the cat."
"Ravi kicked the ball."

Passive Voice

In a passive sentence, the receiver of the action becomes the subject. The doer moves to the end after "by", or is left out entirely.

Subject (receiver) + be + past participle + (by + doer)

"The cat is chased by the dog."
"The ball was kicked by Ravi."

Changing Active to Passive — Step by Step

Step	What to Do	Active Example	Passive Result
1	Move the object to the front	Mei Ling ate the cake.	The cake ...
2	Add the correct form of "be"	(past tense, singular)	The cake was ...
3	Change the verb to its past participle	ate --> eaten	The cake was eaten ...
4	Add "by" + the original subject	Mei Ling	The cake was eaten by Mei Ling.

Choosing the Correct Form of "Be"

Tense	Singular Subject	Plural Subject
Present Simple	is	are
Past Simple	was	were

Present Tense Examples

Active	Passive
The teacher marks the papers.	The papers are marked by the teacher.
My mother bakes a cake every week.	A cake is baked by my mother every week.

Past Tense Examples

Active	Passive
Ali painted the fence.	The fence was painted by Ali.
The children picked the flowers.	The flowers were picked by the children.

Key Rules

The subject and the object swap places: In the active sentence, the subject does the action. In the passive sentence, the object of the active sentence becomes the new subject.
Always add a form of "be": A passive sentence must have "is", "are", "was", or "were" before the past participle. Without "be", the sentence is incomplete.
Use the past participle, not the past tense: Write "was eaten", not "was ate". Write "was written", not "was wrote". The past participle is the third form of the verb.
Match "be" to the new subject: If the new subject is singular, use "is" (present) or "was" (past). If it is plural, use "are" (present) or "were" (past). "The letter was sent." vs "The letters were sent."
Match "be" to the tense: If the active verb is in the present tense, use "is" or "are". If the active verb is in the past tense, use "was" or "were".
"By + doer" can be left out: You can include the doer when the information is important. "The book was written by Roald Dahl." You can leave it out when the doer is unknown or obvious. "The window was broken." (We do not know who did it.)

Common Mistakes

Wrong	Right	Why
The cake eaten by my sister.	The cake was eaten by my sister.	You must include a form of "be" before the past participle.
The letter was wrote by my father.	The letter was written by my father.	Use the past participle ("written"), not the past tense ("wrote").
The windows was cleaned yesterday.	The windows were cleaned yesterday.	"Windows" is plural, so use "were", not "was".
The dog was barked loudly.	The dog barked loudly.	"Bark" has no object, so it cannot be changed to the passive voice.
The flowers is planted by the gardener.	The flowers are planted by the gardener.	"Flowers" is plural, so use "are", not "is".

Clue Words

Signals that a sentence is passive

was, were, is, are followed by a past participle (e.g., was taken, is eaten, were sold, are made)

by followed by the person or thing that did the action (e.g., by the teacher, by the wind)

Signals that a sentence is active

The subject comes first and clearly does the action. There is no "be + past participle" pattern.

Common past participles to know

eaten, written, broken, taken, given, made, built, sold, caught, stolen, painted, baked, cleaned, kicked

Tip: If you see "was/were" or "is/are" followed by a word like "eaten", "written", or "broken", the sentence is almost certainly in the passive voice. Look for the "be + past participle" pattern!

Practice Tips

Ask "Who did the action?": Read the sentence and find who performed the action. If the doer appears at the start and acts on something, it is active. If the doer appears after "by" or is missing, it is passive.
Try the swap test: Take any sentence and try moving the object to the front. Add the correct form of "be" and change the verb to its past participle. If the sentence makes sense, you have successfully changed it to passive.
Check your form of "be": After writing a passive sentence, look at the new subject. Is it singular or plural? Is the tense present or past? Make sure your form of "be" matches both.
Learn common past participles: Many verbs have a special past participle form that is different from the past tense. Keep a list of tricky ones: eat/ate/eaten, write/wrote/written, break/broke/broken, take/took/taken.

Quick Reference

Active vs Passive

	Active	Passive
Formula	Subject + Verb + Object	Receiver + be + Past Participle + (by + Doer)
Example	Ali built the sandcastle.	The sandcastle was built by Ali.
Focus	Who did the action	What was done

Forms of "Be" for Passive

Tense	Singular	Plural	Example
Present Simple	is	are	The floor is mopped every morning.
Past Simple	was	were	The bags were packed by the volunteers.

Active & Passive Voice (P4) (Primary 4)