Correct Answer:
D. My friend said that if he had known, he would certainly have helped me.
Correct answer: My friend said that if he had known, he would certainly have helped me.. The pronouns change (I → he, you → me) and the past perfect conditional stays the same.
Background: In indirect speech, the pronouns change to match the new speaker.
- My friend said that if I had known, I would have certainly helped him.: The pronoun “I” should change to “he”, not stay as “I”.
- My friend said that if he knew, he would certainly help me.: “Knew” and “help” change the tense of the original.
- My friend said if he has known, he would have helped me.: “Has known” is the wrong tense.
Did you know? Third conditional sentences do not backshift further.
Memory trick: Third conditional stays the same; only the pronouns change.