Active and Passive Voice

Core Concepts

• Active Voice: The subject of the sentence is the "doer" who performs the action denoted by the verb.
• Passive Voice: The subject is the receiver of the action; the focus shifts from who did it to what was done.
• The Fundamental Rule: To convert to passive, the object of the active sentence becomes the subject of the passive sentence.

Rules for Conversion

• Verb Structure: Passive verbs are always formed using a specific form of the verb "be" + the past participle of the main verb.
• The Agent: When the doer is mentioned in a passive sentence, they are called the "agent" and are introduced using the preposition "by".
• Transitive Requirement: Only transitive verbs (verbs that take an object) can be turned into passive voice. Intransitive verbs like "smile" or "sleep" cannot be passive.
• Grammatical Consistency: The verb must always agree with the new subject in number and person, while the original tense of the sentence must remain the same.

Tense and Modal Restrictions

• Tense Exclusions: There are no passive forms for the future continuous tense or any of the perfect continuous tenses (present, past, or future).
• Modal Verbs: Passive forms for modals (can, may, might, etc.) use the formula: modal + be + past participle.
• Instruments: While "by" is used for the person doing the action, the preposition "with" is used to describe the instrument or tool used.

Strategic Use of Passive Voice

• When to Use: Use the passive voice when the action is more important than the doer, when you want to be less direct, or to avoid naming names.
• Omission of the Doer: The agent can be left out if the doer is unknown, obvious from context, or simply not important to the message.
• Pronoun Changes: Subject pronouns change to their objective forms when they become agents (e.g., "I" becomes "by me", "she" becomes "by her").

Special Sentence Structures

• Two Objects: If a verb has both a direct and indirect object, the sentence can be written in two different passive ways depending on which object is made the subject.
• Infinitives: Statements with a "to-infinitive" are converted using "to be + past participle".
• Imperative Sentences:
  • For commands, use the structure: Let + subject + be + past participle.
  • For requests or suggestions, use: You are requested/advised + to + verb.
• Interrogative Sentences: Questions follow the same basic transformation rules, maintaining the question format while swapping the roles of subject and object.