The professor's face froze into an inscrutable mask.

He pointed to the stairs, his face remaining an inscrutable mask.

His face was an inscrutable, cruel mask.

What emotions played behind the inscrutable mask of his face?

Marla Karuw's face was an inscrutable mask of determination.

Mrs. Pressman's face was not unlike the model's - an inscrutable mask.

Naltecona looked for a long time at the dying blaze, his face an inscrutable mask.

Despite these telltale signs of nervousness, her face remained an all but inscrutable mask.

Yossarian leaned forward and peered closely into Orr's inscrutable mask of contradictory emotions.

Then the moment was gone, and the unperturbable, inscrutable mask returned.