A woman wearing a blue dress is drawing a picture of a boy and a girl on the sidewalk with sidewalk chalk .
It is improbable that a woman is drawing a picture on the sidewalk in a dress .
It is certain that a woman is drawing a picture on the sidewalk in a dress .
It is improbable that a woman is drawing a picture on the sidewalk in a dress .
A woman is drawing a picture on the sidewalk in a dress .