But his face was perfectly innocent of any particular expression.

Then she looked him in the eye, as if searching for a particular expression.

With no particular expression, she turned her head and spat in his eye.

Where had he seen that particular expression before quite lately?

She leaned on an elbow and looked up at me without any particular expression.

Only one thing can have put that particular expression on his face.

She had seen that particular expression on his face many times before.

Sometimes he looked at me but there was no particular expression.

She had never seen that particular expression on her mother's face.

To the outside world, her smooth face wore no particular expression.