On Sunglasses 

As I was reading I considered the Sunglasses, As another student noted in Humbert Humbert's description of his encounter with Annabel " somebody's lost pair of sunglasses" was the only witness to there embrace. Sunglasses do not leave the book there though, when conceiving his plan to to embrace Lolita at the lake in chapter 11 he plans for his excuse to be that he has misplaced his "wristwatch or sunglasses". In this case the lost sunglasses become and overt allusion to the potentially fictional  encounter with Annabel which Humbert is fantasizing about recreating, though the author leaves it to the reader to make the connection. It appears that Humbert simply playing games with us like he did once with his therapist. The  3rd occurrence of forgotten sunglasses on a beach occurs in chapter 20 when Humbert uses them as an excuse to retreat to the woods where he conceives his plan to kill Charlotte. The latter 2 show the falsity of the former. They are both at the time his deepest fantasy, and the first is his overall fantasy, and idealized version of his relationship with his "first" nyphet. Humbert sees not through the eyes of the boy embracing the girl, but through a pair of lost sunglasses.