Exposition

"I told the driver to go to the Parc Montsouris, and got in, and slammed the door. Brett was leaning back in the corner, her eyes closed. I sat beside her. The cab started with a jerk.
'Oh, darling. I've been so miserable,' Brett said." Page 32

I find Hemingway's execution of exposition very interesting. He approaches the introduction of each character differently. He is straightforward when discussing Robert and fills the reader in on basically his whole life and background. On the other hand, he never reveals much about the narrator, Jake. I'm assuming more is revealed as the story progresses. And then there's Brett. In a way, the author leaves the reader confused when it comes to her. He gives a limited amount of information about her but never fully explains. At the end of this passage, I assumed that the next chapter would explain her former (or present) relationship with Jake. But I was wrong. I am extremely confused. Obviously they had/have some short of romantic relationship but have no commitment to each other. I believe Hemingway leaves the reader guessing to strengthen Brett's character. He wants her character, I think, to be in a shroud of mystery. He wants her to be seen as unpredictable.