Final answer:
The sentence that foreshadows something significant happened in either the house or flower garden is sentence 3. The description of the well-maintained and tidy garden and house implies that something important or noteworthy occurred there.
Step-by-step explanation:
The sentence from the excerpt that foreshadows something significant happened in either the house or flower garden is sentence 3.
The sentence states, "The flower garden is prim, the house a gleaming white, and the pale fence across the yard stands straight and spruce." This description of the house, garden, and fence being well-maintained and tidy implies that something important or noteworthy occurred in this location.
For example, a tragic event or a major change might have taken place that required the narrator to keep the house and garden in pristine condition as a way of coping or holding onto a memory.
Learn more about Foreshadowing in literature