Active and passive constructions refer to two ways of structuring a sentence based on the relationship between the subject, verb, and object. Here’s a detailed explanation of each:

Active Construction

In an active sentence, the subject performs the action expressed by the verb, and the object receives the action. The general formula for an active sentence is:

Subject + Verb + Object

Example: “The dog chased the cat.”

  • Subject: The dog
  • Verb: chased
  • Object: the cat

In this example, the subject (dog) is actively performing the action (chasing) on the object (cat).

Passive Construction

In a passive sentence, the subject receives the action expressed by the verb, and the object (or agent) performs the action. The general formula for a passive sentence is:

Subject + To Be + Past Participle (Verb) + By + Agent (Object)

Example: “The cat was chased by the dog.”

  • Subject: The cat
  • To Be: was
  • Past Participle (Verb): chased
  • By: by
  • Agent (Object): the dog

In this example, the subject (cat) is receiving the action (being chased) performed by the agent (dog).

Here’s are the key differences between active and passive constructions:

FeatureActive ConstructionPassive Construction
Subject’s rolePerforms the actionReceives the action
Object’s roleReceives the actionBecomes the subject of the passive sentence
Agent’s roleSubject of the active sentenceIntroduced by the preposition “by” or omitted
Sentence structureSubject + Verb + ObjectSubject (object of active) + To Be + Past Participle (Verb) + (By + Agent)
Clarity and directnessMore clear and directLess clear and direct
EmphasisEmphasizes the subject and actionEmphasizes the object (subject of the passive) and action
Agent mentioningAlways mentioned as the subjectCan be mentioned using “by,” omitted, unknown, or unimportant
Common usageMore common in general writingMore common in scientific, technical, or legal writing
Preferred in academic and professional writingYes, for clarity and concisenessIn specific contexts, such as when the agent is intentionally de-emphasized or unknown
Effect on sentence lengthGenerally shorter and simplerGenerally longer and more complex

Avoiding the passive voice

In most cases, it’s preferable to use the active voice because it’s more concise, direct, and easier to understand. The active voice clearly shows who or what is performing the action.

Examples of active voice:

  • The student wrote the essay. (The subject “student” performs the action “wrote”)
  • My sister baked the cake. (The subject “sister” performs the action “baked”)
  • The team will announce the new policy tomorrow. (The subject “team” performs the future action “will announce”)

Using the passive voice

While the active voice is generally preferred, there are situations where the passive voice can be useful or appropriate:

  1. When the actor is unknown or unimportant
  • Example: The city was founded in 1792. (We don’t need to know who founded it.)
  1. When you want to emphasize the action over the actor
  • Example: The book was banned by the government. (The focus is on the action of banning rather than who did it.)
  1. When you want to be impersonal or sound objective
  • Example: Mistakes were made during the experiment. (Passive voice avoids directly assigning blame.)
  1. When you want to move the topic to the end of the sentence
  • Example: The final decision will be made by the committee. (Emphasizes “the final decision”)

For certain types of academic writing that prohibit first-person pronouns, the passive voice can be employed when referring to one’s own actions. Avoid dangling modifiers when using the passive voice in complex sentences.

Active Voice with First-Person PronounsPassive Voice to Avoid First-Person Pronouns
I conducted the experiment.The experiment was conducted.
We analyzed the data.The data were analyzed.
I will present my findings.The findings will be presented.
We have reviewed the literature.The literature has been reviewed.
I observed this phenomenon.This phenomenon was observed.