Final answer:
The three major themes in "Winter Dreams" are ambition, disillusionment, and social class.
Step-by-step explanation:
The three major themes in "Winter Dreams" are ambition, disillusionment, and social class. These themes are explored through the protagonist Dexter's desire for success and wealth, his gradual realization of the emptiness and superficiality of his dreams, and the impact of social class on his relationships.