I looked down at the floor to keep my expression to myself.

But she kept her expression even and didn't look away.

Michael took a deep breath and tried to keep a expression on his face.

I tried to keep a blank expression on my face.

She stood watching, quite unable to keep a hopeful expression off her face.

She looked up at him, keeping her expression innocent and friendly.

Julius tried hard to keep a pleasant expression on his face.

Miles kept his expression to no more than a faint, slight smile.

He had been pushing her hands away for the last half hour, trying to keep an expression of distaste off his face.

Hopefully he'd managed to keep his expression free of emotion.