If we hadn't missed our train, we wouldn't have been late for the
conference.
If she had failed her exam in maths, she would have to take the exam again.
If the hadn't told us the truth, we wouldn't have known what to do.
If the plane hadn't arrived on time, we would have had problems with our
luggage.
If I hadn't had any time for the picture gallery, we wouldn't have known
anything about this modern artist.
If the party hadn't been a success, they would have arranged another party.
If we hadn't gone to Brighton, we wouldn't have looked suntanned at all.