A woman wearing headphones walks down the street .
A woman walking down the street .
A woman wearing headphones walks down the street.
A woman walking down the street.
The second sentence implies that the imprtance of the previous sentence was that the woman was walking, rather than the fact that she was wearing headphones.
The second sentence implies that the imprtance of the previous sentence was that the woman was walking , rather than the fact that she was wearing headphones .