Form     If +past perfect + would have +past participle short form: 'd   (=had/would)


  1. To talk about an event that did not happen because of the condition in the if clause. The third conditional is often used for excuses.
  2. To talk about a condition that is unreal because it did not and could not happen.


If I had gone,the other man would have taken the picture. (I didn't go,so I took the picture and the other man didn't.)

If I'd had the money I would have given them some. (I didn't ,so I didn't give them any.)

If I had been born a hudred years ago,I would have had a different life.


The if clause can appear in the second part of the sentence. No comma is used.

I wouldn't have come if I 'd known you were busy.