He made a face, but then his expression grew more serious.

And his own expression grew serious enough when she could see him no longer.

Now that they were on the subject of work, her expression had grown serious.

Rome's expression grew serious, as if he wanted to say more.

Her own expression grew serious as she waited for him to explain.

His expression grew serious again as he thought for a few seconds longer, then nodded once.

Her expression growing serious, she put her head on one side the better to study him.

Father's expression grew harder, but he did not give in to his emotions.

Something must have altered in his face, for the officer's own expression suddenly grew dangerous.

Then, for the first time since the conversation began, her expression grew humorous.