English verbs are said to have two voices: active and passive.

Active Voice: the subject of the sentence performs the action:

His son catches fly balls. Creative children often dream in class.

Note: Verbs in the active voice may be either transitive or intransitive.

Passive Voice: the subject receives the action:

The ball was caught by the first baseman.
The duty is performed by the new recruits.
The dough was beaten by the mixer.
The mailman was bitten by the dog.

Only transitive verbs can be used in the passive voice. What would be the direct object of the verb in the active voice becomes the subject of the verb in the passive voice:

Active voice: The dog bit the mailman. “bit” is a transitive verb. The receiver/direct object is “mailman.”

Passive voice: The mailman was bitten by the dog. “bit” is now in the passive voice. The “receiver” has become the subject of the verb.

A passive verb in either present or past tense will always have two parts: some form of the verb to be (am, is, are, was, were), and a past participle (verb form ending in -ed, -en, or any form used with have when forming a perfect tense).

NOTE: The mere presence of the verb to be does not indicate that a verb is in the passive voice. The test of a verb in the passive voice is the two-part question:

Is the subject performing the action of the verb or is the subject receiving the action of the verb?

If the subject is receiving the action, then the verb is in passive voice.

Sometimes the passive voice is the best way to express a thought. Used carelessly, however, passive voice can produce a ponderous, inexact writing style.