My stomach knotted; it was time to get on the ship.

Cat's stomach knotted at the sound of his son's name.

But she could not even say the man's name as her stomach knotted.

My stomach knotted as I pushed open the heavy door.

His stomach was knotting for the first time in days.

He felt better for half a second, then his stomach knotted again.

He knew what would be in it and his stomach knotted.

His stomach knotted, and he hadn't slept well the night before.

The two of them had given me their full attention, and my stomach knotted.