Q1. Choose the correct answer from the given options: Why did they pull down the building? (Change the voice)
A Why had been the building pulled down?
B Why did the building been pulled down?
C Why is the building been pulled down?
D Why was the building pulled down? Correct
Explanation
The active sentence is in the simple past tense: "Why did they pull down the building?" In passive voice, the object "the building" becomes the subject, and the simple past passive form is "was pulled down". The sentence therefore becomes "Why was the building pulled down?" "Had been" would fit the past perfect passive, not this tense. "Did ... been" is ungrammatical because "did" takes the base form. "Is ... been" also mixes present tense with a past participle wrongly.