12. He speaks too slowly for his students to stay interested.
→ He speaks so slowly that his students get very bored.
→ He doesn't speak fast enough to keep his students interested.

13. It is such a boring book that nobody likes it.
→ The book is not interesting enough for anyone to like.
→ The book is too boring for anyone to like.

14. They were such strong people that they could lift the rock.
→ They were strong enough to lift the rock.

15. It is such a hard question that she can't answer it.
→ The question is not easy enough for her to answer.
→ The question is so hard that she can't answer it.

16. It was such a hard cake that we couldn't eat it.
→ The cake was not soft enough for us to eat.
→ The cake was so hard that we couldn't eat it.

17. It was such bad weather that we couldn't go out.
→ The weather was so bad that we couldn't go out.
→ The weather wasn't good enough for us to go out.
→ The weather was too bad for us to go out.

18. John is too young to join the club.

19. It was such wonderful news that she decided to have a celebration.
→ The news was so wonderful that she decided to have a celebration.

20. It is such a dirty restaurant that no one wants to eat there.
→ That restaurant is not clean enough for anyone to want to eat there.
→ That restaurant is too dirty for anyone to want to eat there.

21. It was such a boring film that we left before the end.
→ The film wasn't interesting enough for us to stay until the end.
→ The film was too boring for us to stay until the end.

22. He spoke too quickly for me to understand what he said.

23. The ship is so far that we can't see it.
→ The ship is not close enough for us to see.
→ The ship is too far for us to see.

24. She wasn't early enough to meet her.
→ She was too late to meet her.

25. It was such hot tea that we couldn't drink it.
→ The tea was not cool enough for us to drink.
→ The tea was so hot that we couldn't drink it.