Passive voice verbs are usually used in writing than in speech. They are used in some types of writing such as in journalism (newspapers, magazines) and in all types of scientific and technical writing. Scientific articles often contain more passive than active sentences. You should not use passive voice verbs if you don’t have to.
In active sentences the subject of the sentence is the actor of the verb or the doer of the action.
Bill kicked the ball.
In the above sentence, the subject Bill is the actor of the verb or the one who kicked the ball. The direct object the ball is the receiver of the verb action.
In passive sentences the subject of the sentence is the receiver of the action.
The ball was kicked by Bill.
In the above sentence, the ball is the receiver of the action and is the subject of the sentence. Bill, the actor of the verb is the object of the preposition by.
To form a passive sentence from an active sentence:
- Move the receiver of the action from the direct object position of the sentence to the subject position of the sentence.
- Insert the verb BE in agreement in number with the new subject and in the appropriate tense.
- Change the verb to its past participle form.
- Optionally place the actor of the verb in the object position after the preposition by.