RULES TO CHANGE FROM ACTIVE TO PASSIVE
An idea can be expressed in two different ways. We can do it by using a verb to indicate whether the subject performs an action (active voice) or receives the action (passive voice).
Active voice: The verb is in the active voice when the subject does the action.
EXAMPLE: The girl drank juice. (Subject: The girl / Verb: drank / Object: juice)
Here, the doer of the action is the girl and the verb "drank" is in the active voice.
Passive voice: When action is done to the subject, the verb is in the passive voice. The previous object (Juice) is now used as the subject.
EXAMPLE: Juice was drank by the girl. (Verb: was drunk / Subject: Juice)
Here, action is done to the subject and the verb "was drank" is in the passive voice.
In changing a sentence, as above, from active voice to one in the passive voice, we make the object of the active voice sentence the subject of the passive voice sentence.
1.The verb used in a passive voice sentence is formed by adding the past participle to "to be" (am, is, are, was, were, has been, have been, will be, etc.) depending on the tense of the active voice.
2. The same tense form is maintained while changing from active to passive.
3. Only verbs which take on an object can be changed to the passive. (Example: She laughs loudly. This sentence has no object, so it's not possible to turn it into a passive sentence.)
4. When we choose passive sentences, we use the preposition 'by' to show who or what does or has done the action (as shown above: Juice was drunk by the girl.) We use 'by' only when we have to.
VERBS WITH TWO OBJECTS
A verb can have two objects – a person and a thing. Such a verb can have two possible passive voices.
Active: The salesman shows Zenith a new LCD T V. / The salesman shows a new LCD TV to Zenith.
Passive: Zenith is shown a new LCD TV. (by the salesman).
Passive: A New LCD TV is shown to Zenith (by the sales man).