Frames just one character as the star of the shot to focus on emotion. If no one else is visible at all, it's a clean single. If the other person's shoulder slightly overlaps the edge, it's a dirty single.
Watching one person's reaction in a conversation (dirty single), showing the isolation of a character left alone (clean single).
Not verified — write it so the other person overlaps the frame smaller and blurrier than in an over-the-shoulder shot.
Dirty single, close-up on a woman listening to bad news across a table, the blurred shoulder and ear of the man facing her sit at the left edge of the frame, only her face in sharp focus, her eyes slowly fill with tears, locked-off camera, 85mm lens, soft window light, tense quiet mood, 5-second shot.
dirty single, close-up on the woman, the man's blurred shoulder at the left edge of the frame
Not verified