Final answer:
Sentence 3 foreshadows something significant happening in the house or flower garden.
Step-by-step explanation:
The sentence from the excerpt that foreshadows something significant happening is sentence 3. This sentence mentions the flower garden and the house, indicating that something important may have occurred in either of these locations. Foreshadowing is a literary device used to provide hints or clues about events or outcomes that may happen later in the story. In this case, the description of the prim flower garden and the gleaming white house suggests that there may have been a change or development that the narrator is reflecting upon.
Learn more about Foreshadowing in literature