14. You had better go home and have a rest now.
→If I were you , I would  go home and have a rest now
15. She forgot to add salt, so the food was tasteless.
→If she hadn't forgotten to add salt, the food hán't been tasteless.
16. Because the evidence was withheld, the prisoner was found guilty.
→Had  the evidence not been withheld,  the prisoner would have been found guilty.
17. He would have lent you his violin if you'd asked him.
→Had you asked him , he would have ent you his violin