An adaptation of the Catechism for Young Children in modern English.
Question: Who can change a sinner’s heart?
Answer: Only the Holy Spirit.
Question: Who can change a sinner’s heart?
Answer: The Holy Spirit alone.
The answer is sharpened to “only the …” instead of “… alone”. Unlike previous questions, “The Holy Spirit alone” is not a specific theological phrase (c.f. “The bible alone”) so the simpler construction is preferred.