Let us now understand the rules for changing into Passive Voice.

Rule 1 :

The 'object' of the verb in the Active Voice becomes the 'subject' of the verb in the Passive Voice and the 'subject' in the Active Voice becomes the 'object' in the 'Passive Voice'.

For example: In the active voice, the sentence is

My mother cooks the food. Here, Mother is the subject and the cooks is the verb. Food is the object of the sentence. In the passive voice, the sentence becomes: The food is cooked by my mother. Here, the Food becomes the subject of the sentence, and the Mother becomes the object of the sentence.

Rule 2

The main verb is changed into the Past Participle. The third form of the verb and an appropriate form of the helping verb according to the 'Tense' of the sentence is used.

Note in the above example, the main verb cooks in the active voice has changed into is cooked in the passive voice, which is in past participle form.

We would be discussing more about this rule in the further modules.

Rule 3

The 'subject' in the Active Voice' becomes the 'object' in the Passive Voice and the word 'by' is generally placed before the object.

As in the above example

Mother, which was the subject of the sentence in the active voice has been changed to the object in the passive voice. Similarly, food, which was the object of the sentence in the active voice has been converted to a subject in the passive voice. Note, we have placed by before the object mother in the passive voice.

In order to convert from active to passive voice, we use two types of construction

Construction 1: By + agent
This construction is used only when the agent is definite and important.
(Note: Agent is nothing but the subject of the sentence in the active voice )

For example:
Mohan reads a poem.
In passive voice, this sentence becomes: A poem is read by Mohan.

Note, here the agent which is Mohan is definite, hence in the passive voice, we are using the construction "by + agent".

Construction 2: Without 'by' + agent is not used when the agent is vague.

Let us see this sentence:
(i) Someone broke the window.

In passive voice, this sentence becomes:

The window was broken.

Note in this sentence, the subject of the sentence, is vague, as someone is not definite but a vague reference to somebody. Hence, the construction by + agent has been omitted here.

Note, while changing active to passive voice,

The Nominative case of the pronoun is changed into the objective case.

For example:

• He changes to him
• She changes to her
• I changes to me
• We changes to us
• They changes to them
• You remains the same as You
• It remains the same as it

Another important point to note is that:

If a TransitiveVerb has two objects, either of them may be made the subject in the Passive Voice the other remains unchanged.

For example:

She gave me a pen.
Here, we have two objects, me and pen.

The passive form of the sentence will become:
I was given a pen by her OR A pen was given to me by her.

Read More: Definite Article: Use Of "The" - Rules - English Grammar