Imagining the Past

As you might already know, we use the third conditional to say that if a different action was taken in the past, the result would have been different. For example: If I had studied hard, I would have passed the exam. (But the fact is that you didn't study, so you failed the exam.) This is the opposite of reality. But unfortunately, you can't change the past. You have no other choice than to accept the past. So the probability of this conditional is zero.

The structure of the third conditional is:

if + past perfect simple, would + present perfect simple.


However, we can alter either half of the third conditional with a continuous tense to create what is called a continuous conditional to talk about an action happening at a particular time or during a period of time in the past. 


For example, we can use if + past perfect continuous to imagine an action at a particular time in the past. 

If you had been looking for me at the station, I wouldn’t have taken the train. (But you didn’t look for me, so I had to take the train!)

Or we can use would + present perfect continuous. in the consequence half of the third conditional to imagine a action during a period of time in the past. 

I would have been waiting for the train if you hadn’t picked me up at the station. (Fortunately though, you picked me up, so I didn’t have to wait for the train!)

To review conditionals, check out the entry Conditional Review.