Would you be so kind as to correct a new portion of sentences? I would also appreciate it if you would comment on your changes (if there are any changes, of course)

1. The back cover of the book read/said: “Combine light reading with serious problems raised by the author”.
2. As it turned out a few minutes later he hadn’t had to combine the liquid with soap.
3. I hear they’ve combined again.
4. I think she shouldn’t have come down so hard on the children just for making a mess of the carpet.
5. The punishment Jack had to suffer was really sound.
6. The chaotic situation made the local authorities confess that they did still not have a definite plan for defusing the explosive situation.
7. –I find this new mechanism to be very ingenious. What do you think of it? –It’s really great! Do you know who devised it? – Peter? –Yes. I’ve no idea why he preferred to stay here. He had so many chances to leave for rich countries. He could get loads of money! I’d definitely go abroad if I could devise such complex and ingenious mechanisms.
8. For some period of time they even thought a way out of the situation was close. But they did not know about the enemy’s fiendish plan to attack suddenly.
9. The leading constructors of the country say that the project of the building was very sound. Having watched the video tape twice very carefully they have not found any mistakes the builders could have made in the course of putting up either. Therefore, the cause of the collapse still remains a matter for conjecture.
10. She was rather vague about the details of the accident, so the police found it very difficult to get something new from her.
11. It always seemed to me that there was only one feasible solution to the problem. If Jane hadn’t come up with that great idea then I’d probably have put my plan into action. Nobody knows what would have happened in this case. Now that about 7 years has passed, I realize that my plan combined both good and bad points. I’d even say there were heaps of stupid ideas in my plan.
12. When he heard that question he frowned. It was clear he didn’t know how he should answer. On the one hand, he couldn’t tell the truth because they would have killed him for it. On the other hand, he was fed up with the plans of the party.
13. Their exhibit stood no comparison with the rest presented at the exhibition.
14. He’s going to aim all his criticism at common people.
15. How are you ever going to catch up? You were given the task of attempting to implement new means of communication in our department at the beginning of the month!