How does the author use foreshadowing in Three Tall Women?

In Act I, Part IV, A's reference in passing to the Son liking boys indicates that the Son is gay, while B's disgusted reaction foreshadows her rage at him in Act 2. This entire exchange foreshadows the revelations and confrontations in the final quarter of the play, as this woman at all her ages in the second act (A, B, and C), confronts the Son in memory and in person.