• In active sentences the subject is "a word or phrase that denotes the doer of the action, while in passive constructions, the subject is the receiver of the action."

• 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)

• ACTIVE TENSES AND PASSIVE EQUIVALENTS

Notice that the tense of the verb to be in the passive voice is the same as the tense of the main verb in the active voice.

Example: to change