Tottering uncertainly, Roberta happened to observe the head engineer's shocked expression.

Keen eyes observed the young man's expression.

It took him a moment or two to re-establish himself in the here and now, and observe her expression.

Observing my expression, she broke off, and again studied me thoughtfully.

Mark, observing her blissful expression, grinned to himself.

I only had one quick glance at him, but that was enough to observe his same old expression, both sad and serene.

The valet returned a smug grin when he observed his master's expression.

"Is it ever a bad idea to observe a suspect's expression at the instant she learns the body was discovered?"

Her trademark grin flashed as she observed his expression.

Observing Walter's bemused expression, he poured an even stiffer one and pressed it into his brother's hand.