11.   I did my best to concentrate on each movement, but when I glanced at the mirror, my jaw was set and my brows furrowed.

12.   Roberson asked Markenson, whose brow furrowed as she tried to remember.

13.   Their brows furrowed.

14.   Then his brow furrows a bit again.

15.   When the priest begins his lesson, pointing at pictures and brief written explanations of the new euro notes and coins, brows furrow and milky eyes strain.