The story is told by an omniscient third-person narrator. The narrator is not a character in the story, but can look down on the events and know and see everything that is happening, and has information that the characters themselves do not have.
The narrator is more interested or in Sylvia's thoughts and feelings than is shown to any other character. The story is primarily told in the past tense with three shifts into present tense.
The narration of this story has been a source of discussion that has divided critics. From the eNotes critical overview, "The matter of shifts in narrative stance has likewise been controversial. It was seen first as a weakness. ...More recently, the shifting has been regarded as an interesting and effective choice...".