The voice of the verb shows whether the grammatical subject performs the action or is acted upon. A careful writer chooses active voice over passive voice whenever possible. Because active voice expresses a direct statement, it is preferred.
Notice that the active voice sentence places the “doer” of the action in the grammatical subject slot and the “receiver” of the action (that which is being acted upon) is placed in the object slot. The passive voice is just the opposite. The “receiver” of the action is in the subject slot, and the “doer” of the action is placed in the object slot. A be verb is also added. (HINT: If a be verb is NOT followed by an -ing verb, the sentence is passive.)
In the active voice sentence, the original “doer” is John. John is in the subject slot. In the passive voice sentence, the “doer” of the sentence, John, is placed in the object slot by using by. The original “doer” becomes the object of the preposition by. The grammatical subject of the passive voice sentence, novel, is the original object of the active verb read.
Although active voice is preferred, there are a few instances when the use of passive voice is acceptable:
Avoid awkward use of the passive voice:
Do not shift from active to passive voice within a passage:
Remember: In formal writing, active voice is preferred. However, when the "doer" of the action is unknown or irrelevant, passive voice may be used.
In this formula, the tense is found in the be verb, and the -en form is found on the main verb:
Example: For the verb help, (past tense + BE = was;) (-en + help = helped). Thus, the passive voice is was helped.