`11. `Were you to change your mind, I would be most grateful.

`12. `Should she decide to come, please telephone.

`13. `Had he understood the problem, he wouldn't have committed those mistakes.

`14. `Had I known about those problems, I would never have moved here.

`15. `Had he not resigned, we would have been obliged to give him the sack.

-------------------------

Đảo ngữ câu điều kiện : 

Câu điều kiện loại 1 :Should + S + (not) + V + … + S + will/may/can + V

Câu điều kiện loại 2 : Were + S + (not) + … + S + would/might/could + V

Câu điều kiện loại 3 : Had + S + (not) + been +... + S + would/might/could + have + V3/Ved