The third conditional

The third conditional in English is used to talk about situations that have not really taken place, these are hypotheses. Very often they are used to talk about something that we regret, but also to reproach something or simply to imagine a situation that could have developed in a different way.

https://www.google.com.co/search?q=third+conditional&rlz=1C1AVNG_enCO650CO650&source=lnms&tbm=isch&sa=X&ved=0ahUKEwiFjtPnyKneAhXpx1kKHeqLCbMQ_AUIDygC&biw=1366&bih=657#imgrc=wcYPhrsehcDxnM:

https://www.youtube.com/watch?v=TcrN0N8o494&t=26s