Passive Voice in English

Passive voice is used when the focus is on the action

When to use passive voice

• Use passive voice when you do not wish to emphasize the subject of the sentence. 
• Also use passive voice when you wish to emphasize what happened and the person or thing acting is unknown or unimportant.  

In a passive clause, we usually use a phrase

beginning with by if we want to mention the agent–the person or thing that does the action, or that causes what happens.

• Water is also released into the atmosphere by plants through photosynthesis.

We normally make passive forms of a verb by using tenses of the auxiliary be followed by the past participle (=pp) of the verb. Here is a list of all the passive forms of an ordinary English verb, with their names.