Select the option that expresses the given sentence in active voice.
The classroom lights have been left on again.
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → Someone has left the classroom lights on again.
Active form of the present perfect passive with no doer:
| Change | Passive | Active | Why |
|---|---|---|---|
| Doer added as subject | (no doer named) | Someone | The passive does not say who left the lights on. So the active uses “Someone” as the subject. |
| Tense kept | have been left | has left | “Have been left” is the present perfect passive: has / have been + past participle (V3). So the active stays in the present perfect: has / have + V3. “Has” because “someone” is singular. |
| Subject becomes object | The classroom lights | the classroom lights (after the verb) | The lights receive the action, so they go after “has left”. “On” stays after them. |
| Full sentence | The classroom lights have been left on again. | Someone has left the classroom lights on again. |
Other present perfect passives with no doer change back the same way: has / have been + V3 → Someone has + V3. Example: My bicycle has been moved to the back of the shed. → Someone has moved my bicycle to the back of the shed.
Why the Other Options are Incorrect?
Option 2: Someone had left the classroom lights on again. — Incorrect. “Had left” is the past perfect. The passive “have been left” is the present perfect.
Option 3: Someone have left the classroom lights on again. — Incorrect. “Have” does not agree with “someone”. “Someone” is singular, so it takes “has”.
Option 4: Someone left the classroom lights on again. — Incorrect. “Left” is the simple past. The passive “have been left” is the present perfect, so the active needs “has left”.