For a long time he looked deep into her face with a serious expression.

He was looking at me with an expression I couldn't read.

And at me, with an expression I could not name.

She looked at me for a moment longer with an expression I couldn't read.

He was looking at me in a particularly level way, with an expression I could not understand.

He did not move, but looked at her with a serious expression on his face.

And he come out with the same expression on his face.

But she would only look back at him with the same expression on her face.

He just sat there looking at me with the same still expression.

The young men looked at each other with an expression of fear.