We will explain how we did it. (Passive)

Active Voice: We will explain how we did it. 
Passive Voice: How we did it will be explained by us. (অপশন 'গ')

• Future Indefinite যুক্ত Active Voice কে Passive Voice করার নিয়ম -
→ প্রথমে object = how we did it, passive voice- এ subject রূপে বসবে।
→ Passive voice- এ How we did it এর পর shall/will + be বসবে।
→ এরপর verb = explain এর past participle form = explained বসবে।
→ এরপর by বসবে।
→ 'by' এরপর active voice এর subject = We, passive voice এ object = us রূপে বসে।