Original: كَتَبَ الطَّالِبُ الدَّرْسَ — The student wrote the lesson.
1. Change active «كَتَبَ» to passive كُتِبَ.
2. Omit the overt agent الطَّالِبُ.
3. Promote the original object «الدَّرْسَ» to nominative الدَّرْسُ.
Result: كُتِبَ الدَّرْسُ — The lesson was written.