Brim pinched the bridge of his nose in mock concentration.

Relieved, she screwed up her face in mock concentration.

He wrinkled his brow in mock concentration.

Chekov screwed up his face in mock concentration.

He knuckled his forehead in mock concentration, then snapped his fingers triumphantly.

The look of mock concentration on his face made me laugh.

"But sometimes I can read minds..." He put his forefinger to his lower lip in mock concentration.

She squinted her eyes in mock concentration, as if she were struggling to think of something he would be hard-pressed to find on such a well-provisioned starbase as Vanguard.

He peered into display with mock concentration, wrinkling his nose.