1. If she wasn't late (not/be late), she wouldn't have missed the train.
2. If it wasn't cold (not/be cold), they wouldn't have lit the fire.
3. They wouldn't see (not/see) the Queen if they hadn't visited London on that day.
4. If they locked (lock) the door, the burglars wouldn't have got in.
5. If she opened (open) the letter, she would have been surprised.