Sure! Here are the rewritten sentences as per your instructions:

36. I last saw her three years ago.
**I haven’t seen her for three years.**

37. Because Hoa worked hard, she passed the exam. (so)
**Hoa worked hard, so she passed the exam.**

38. When he was a child, he often played soccer.
**He used to play soccer often when he was a child.**

39. “What is your address?” Lan asked.
**Lan asked me what my address was.**

40. We have never stayed at a worse hotel than this.
**This is the worst hotel we’ve ever stayed at.**