Here’s the rewritten text with inverted conditional sentences:

1. **Had he known** she was sick, he would have visited her.
2. **Were it to be true**, how would we laugh?
3. **Had it not been for** the attendance of a famous star, the party wouldn’t have been successful.
4. **Had I not been there**, the passing of the bill wouldn’t have been prevented.
5. **Were I the author**, I would ask him to sign my copy of his new book.
6. **Had I known** the author, I wouldn’t have been so naive about his book.
7. **Would you let me know** if you wish to keep the books any longer?
8. **Should you break down** on the rough mountain road, take plenty of spare parts.
9. **Were the patient to die**, he would have had to be resuscitated.
10. **In case you were to get lost** in those mountains, you should take plenty of spare parts.
11. **Should you procrastinate**, you might get lost in the mountains.
12. **Had I known** he would die, I would have taken a map.
13. **If he had to study** for his exam, he would.
14. **If he didn’t remember**, he would go to buy a car.
15. **If you don’t enjoy** the party, you can leave anytime.