He gave me a long, level look over one shoulder.
He hit me while I was looking back over my shoulder.
She'd taken to looking over her shoulder for him, and didn't like the feeling one bit.
He looked back over his shoulder at the world they had left.
She got up at once, came around and looked over his shoulder.
He felt rather than saw the line fall over his shoulder.
At the last second, I once again look over my shoulder.
But I can't be looking over my shoulder every second of the day.
He looked over his own shoulder and saw the thing again.
She got up and came to look over my shoulder.