Explanation
The farmer ploughed the field means کسان نے کھیت میں ہل چلایا
Correct Passive Voice: The field was plouged by the farmer.
Past Indefinite tense
Active Voice= Subject + Second Form of Verb + Object.
Passive Voice = Object + was/were + third of verb + by + subject.
Plough is a regular verb which means ہل چلانا
Ploughed is second and third form of Plough.
Field means کھیت
Farmer means کسان