Consider these two sentences:
I am trying to work with children.
I am trying to work, with children.
The former denotes a dedicated student of early childhood education working toward becoming (we hope!) one of our fabulous teachers in a Bright Horizons center.The latter paints a picture of a mom or dad with a spreadsheet in one hand, cheerios in the other, and the exasperated face of someone trying to simultaneously placate a toddler and make a deadline after the nanny called in sick.
And all it took was a comma.