What is one example of foreshadowing?

Elizabeth Bowen's "The Demon Lover" is a complex story that can be read as a psychological thriller, a ghost story, or a murder mystery.  And though readers and critics alike debate Bowen's intended meaning, they can recognize examples of foreshadowing regardless of which interpretation they favor. 

First, the title itself serves as an example of foreshadowing; it is an allusion to an English ballad of the same name in which a scorned lover, back from the dead, comes to his ex fiance's wedding (to someone else, of course), to claim her for himself.  Readers familiar with this reference can expect, once they begin reading the story, that Mrs. Drover's ex-fiance, who was "missing, presumed dead," might return for her.  Such a reading would suggest that Bowen intended to construct a ghost story in her writing of "The Demon Lover."

Other critics, disagreeing with the ghost story interpretation, suggest that "The Demon Lover" is a psychological drama that shows the effects war can have on an already-fragile psyche.  In this case, direct characterization of Mrs. Drover tells readers that her "most normal expression was one of controlled worry."  Furthermore, we learn that Mrs. Drover, as the result of a serious illness that coincided with the birth of a child, has an "intermittent muscular flicker to the left of her mouth."  Those who view Mrs. Drover's encounter in the cab as a hallucination--the result of a psychological breakdown--might have viewed her worry and muscular flicker as signs of a nervous disorder.  In this case, Mrs. Drover's history of such signs foreshadows her breakdown at the end of the story.