A sentence has been given in the active voice. Out of the four given alternatives, select the one which best expresses the same sentence in the passive voice. The workers are building the house.

Introduction / Context:
This question checks your knowledge of forming the passive voice of a present continuous tense sentence. The original sentence, The workers are building the house, describes an action that is in progress at the present time. You must choose the passive sentence that preserves both the tense and the meaning, while correctly changing the focus from the doer to the receiver of the action.

Given Data / Assumptions:

• Active sentence: The workers are building the house.
• Subject: The workers.
• Verb phrase: are building (present continuous).
• Object: the house.
• The passive voice sentence must keep present continuous and mention the house as the subject.

Concept / Approach:
To change a sentence from active to passive voice, the object of the active sentence becomes the subject of the passive sentence. For present continuous tense, the passive structure is: am or is or are plus being plus past participle of the main verb. Here, build is the base verb and built is the past participle. The time reference must remain present and ongoing, so we must keep is being built, not was being built or was built. The agent the workers can appear after by if we want to keep the information about who is performing the action.

Step-by-Step Solution:
Step 1: Identify the object in the active sentence: the house.Step 2: Move the house to the subject position of the passive sentence: The house.Step 3: Recognise that present continuous in active form is are building, so the passive requires is being built for a singular subject.Step 4: Use is because the new subject the house is singular.Step 5: Add the agent phrase by the workers to show who is doing the building.Step 6: Combine all parts to form The house is being built by the workers and match this with the correct option.

Verification / Alternative check:
Convert the chosen passive sentence back to active voice. From The house is being built by the workers, we identify the workers as the doer, use the present continuous are building, and take the house as the object again, recreating The workers are building the house. This confirms that the tense and meaning are preserved. None of the other options give a present continuous passive that can be reversed to the original sentence without changing the time reference.

Why Other Options Are Wrong:
Option A: The house was being built by the workers uses past continuous tense, suggesting the action was happening at some time in the past, not right now. Option B: The house was built by the workers is simple past tense, describing a completed action, and lacks the sense of ongoing activity. Option C: The house is built by the workers is simple present passive, which could describe a habitual action rather than a specific current activity. Only option D correctly captures the idea that the building is in progress at the present moment.

Common Pitfalls:
Students often forget to include being in the passive form of the continuous tenses, producing structures like is built instead of is being built. Others confuse present continuous with simple present and select sentences that talk about general truths rather than current actions. To avoid these mistakes, always break down the original verb phrase into tense and aspect: here, present (are) plus continuous (building). Then build the passive with the same tense and aspect using be plus being plus past participle. Doing this systematically will help you form passive sentences accurately every time.

Final Answer:
The correct passive form of the sentence is The house is being built by the workers.