Sure! Here are the rewritten sentences:

26. If she had known you were in the hospital, she would have visited you.
27. Unless she was very shy, she would enjoy parties.
28. If it had not been raining, I would have taken the children to the beach.
29. Unless the examiner had read the passage very quickly, the candidates would have understood.
30. If people didn’t drive very fast, there wouldn’t be so many accidents.
31. If I knew his address, I would write to him.
32. If they hadn’t asked him to leave the dining room, he would have stayed.
33. Unless you keep silent, you will wake the baby up.
34. If he had worked hard at school, he would have gotten a good job when he left.
35. Unless you stop talking, you won’t understand the lesson.
36. If you stopped smoking, you would feel better.
37. If the boy weren’t so young, he could go to school.