Ananda Paramitha: Passive voice

Passive voice is a grammatical voice common in many of the world's languages. Passive is used in a clause whose subject expresses the theme or patient of the main verb. That is, the subject undergoes an action or has its state changed. A sentence whose theme is marked as grammatical subject is called a passive sentence. In contrast, a sentence in which the subject has the agent role is called an active sentence, and its verb is expressed in active voice. Many languages have both an active and a passive voice; this allows for greater flexibility in sentence construction, as either the semantic agent or patient may take the syntactic role of subject.
Transforming an active verb into a passive verb is a valence-decreasing process ("detransitivizing process"), because it transforms transitive verbs into intransitive verbs.
The use of passive voice allows speakers to organize stretches of discourse by placing figures other than the agent in subject position. This may be used to foreground the patient, recipient, or other thematic role. Passive voice may also be useful when the semantic patient is the topic of on-going discussion
Passive voice is used when the focus is on the action. It is not important or not known, however, who or what is performing the action.

Example: My bike was stolen.

In the example above, the focus is on the fact that my bike was stolen. I do not know, however, who did it.
Sometimes a statement in passive is more polite than active voice, as the following example shows:

Example: A mistake was made.

In this case, I focus on the fact that a mistake was made, but I do not blame anyone (e.g. You have made a mistake.)

Form of Passive

Subject + finite form of to be + Past Participle (3rd column of irregular verbs)

Example: A letter was written.

When rewriting active sentences in passive voice, note the following:

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)

Examples of Passive

Passive Sentences with Two Objects

Rewriting an active sentence with two objects in passive voice means that one of the two objects becomes the subject, the other one remains an object. Which object to transform into a subject depends on what you want to put the focus on.