When talking about something that didn’t happen in the past, many English speakers use the conditional perfect (if I would have done) when they should be using the past perfect (if I had done).
For example, you just found out the truth about somebody. Your friend asks why you didn’t share the information yesterday. You explain that you had not known the truth the last time you saw each other. To express this, you can use an if – then clause. The correct way to say this is with the past perfect in the if clause, and the conditional perfect in the then clause:
|If I had known, [then] I would have told you.
The conditional perfect can only go in the then clause – it is grammatically incorrect to use the conditional perfect in the if clause:
Here are some more examples:
|If I had gotten paid, we could have traveled together.
|If you had asked me, I could have helped you.
The same mistake occurs with the verb wish. You can’t use the conditional perfect when wishing something had happened. Again, you need the past perfect.
|We wish we had known.
|Tom wishes you had stayed.
|I wish they had been honest.