Voice is a grammatical category that applies to verbs. Voice expresses the relationship of the subject to the action.
In a sentence written in the active voice, the subject of sentence performs the action stated by the verb.. In a sentence written in the passive voice the subject receives the action.
Passive voice is used when the focus is on the action. Sometimes it is not important or not known who or what is performing the action.

Active voice: William Shakespeare wrote Hamlet in 1602


Passive voice: Hamlet was written by William Shakespeare in 1602

When rewriting active sentences in passive voice, follow these rules:

  • the object of the active sentence becomes the subject of the passive sentence
  • the finite form of the verb is changed (to be + past participle)
  • the subject of the active sentence becomes the object of the passive sentence (or is dropped)


Active and Passive Voice

 Tense Active Passive
Simple Present Once a week, I clean the house. Once a week, the house is cleaned by me.
Present Continuous I am writing the letter. The letter is being written by me.
Simple Past They built the house last year. The house was built last year.
Past Continuous They were discussing this question when he entered the room. This question was being discussed when he entered the room.
Present Perfect Many visitors have visited that city. That city has been visited by many visitors.
Present Perfect Continuous Mike has been doing this work for two hours. This work has been being done by Mike for two hours. 
Past Perfect He showed me the book which his father had written. He showed me the book which had been written by his father.
Past Perfect Continuous They had been discussing the plan for 3 hours before I came. The plan had been being discussed for 3 hours when I came.
Simple Future
(will)		 They will finish the work today. The work will be finished today.
Simple Future
(be going to)		 I am going to send him a letter. A letter is going to be sent by me.
Future Continuous
(will)		 I shall be writing a letter to him tomorrow A letter will be being written tomorrow
Future Perfect (will) We will have translated the article by 3 pm  The article will have been translated by 3 pm.
Future Perfect
(be going to)		 We are going to have translated the article by 3 pm The article is going to have been translated by 3 pm.
Used to I used to pay all utility bills. All utility bills used to be paid by me.
Must You must see this film This film must be seen
Future Simple in the Past
(would)		 He said that they would built the house next year He said that the house would be built next year.
Future Perfect in the Past
 I said that I should have built the house by January I said that the house would have been built by January