How does the author use foreshadowing in Plenty?

In Act I, Scene IV, the playwright uses foreshadowing extensviely. First, the conversation between Alice and Susan about younger men that foreshadows Susan's relationship with a younger man in the next scene. Second, the appearance of the gun and Brock's comments that foreshadow the violence that explodes from Susan in the second act. Lastly, Brock's reference to money foreshadows the thematic references to "plenty" later in the play, and the second act scene in which Susan comments on how she and Brock are "rotten" with money.