What is the structure of the present simple in passive form?

• S + is/am/are + V3 + (by + O).
• S + V1 + O.
• S + was/were + V3 + (by + O).

What is the structure of the past simple in passive form?

• S + V2 + O.
• S + is/am/are + V3 + (by + O).
• S + was/were + V3 + (by + O).

The losers were eliminated by the guards.

What is the correct passive form of this sentence? “The teacher explains the lesson.”

• The lesson is explained by the teacher.
• The lesson was explained by the teacher.
• The teacher is explaining the lesson.