The Question and Answer section for Washington Square is a great resource to ask questions, find answers, and discuss the novel.
Morris spends an inordinate amount of time with Lavinia Penniman because she supports his interest in marrying Catherine. Lavinia is his one ally.
Over the course of the novel, we come to see that Dr. Sloper sees Catherine as falling short of his expectations. As a result, Catherine cannot seem to garner her father's approval. In the end, Catherine comes to see that her father's vision of...
Sorry, this is only a short answer space.