I've been asked a couple of times lately to explain the difference between narrative and exposition. Sounds like a great blog topic to me!
Narrative -- narrative links the dialogue together. For instance: Tom crossed the floor and picked up the antique vase, wondering where it had come from.
Exposition -- exposition tells us what happened in the past and catches us up-to-date. For instance: When he'd been working as an excavator in Mexico, he'd seen some artwork that reminded him of the designs on this vase. But in Mexico, his mind had been on anything but art. Instead, his days and nights had been consumed by thoughts of a certain dark-eyed girl and the way she flicked her hair over her shoulder as she walked away from him. Always walking away from him.
Essentially, narrative tells us what's going on now and exposition tells us what did go on, a little while ago. It's a past and present thing.