How can we express that a past condition has a result in the present, or that a present condition could have had a (hypothetical) past result? With the mixed conditionals.
There are more possible 'combinations'; for example, with future situations, but we will focus on the ones mentioned above:
a) Past condition with a result in the present: If I had bought that house, I would be living in it now.
b) Present condition with a past result: If she were Spanish, she could have become the Spanish Prime Minister.
An interesting article from The Guardian, talking about all the things that the teachers are looking forward to telling the parents... but can you imagine if they did?