Converting an active voice sentence to passive voice involves shifting the focus from the doer of the action to the receiver of the action. The original sentence, "They were repairing the road," is in the past continuous tense (subject + was/were + -ing form of verb + object). When converting continuous tenses to passive voice, the structure is 'object + form of 'to be' (matching original tense) + being + past participle of the main verb'.
In the given sentence, 'the road' is the object, 'were repairing' is the verb phrase, and 'they' is the subject. To form the passive voice, 'the road' becomes the new subject. Since 'the road' is singular and the original tense is past continuous, we use 'was'. We then add 'being' to maintain the continuous aspect, followed by the past participle of 'repair', which is 'repaired'. Thus, the correct passive voice is The road was being repaired.
- The road was repaired is incorrect because it uses the simple past passive, which changes the aspect from continuous (ongoing action) to simple (completed action).
- The road is being repaired is incorrect because it uses the present continuous passive, changing the tense from past to present.
- The road has been repaired is incorrect because it uses the present perfect passive, which changes both the tense and aspect, implying completion in relation to the present, not an ongoing past action.