somebody's face falls

He looked at the next line, and his face fell.

Then his face fell, and he spoke almost to himself.

He was surprised, and I believe his face fell a little at the news.

He held up his hands when the faces of the four men at the table fell.

She turned toward me and her face fell into shadow.

But then her face fell, as if the weight of the lie was too much.

Her face fell a little when she saw I wasn't carrying anything.

Her face turned a little and fell away from him down the pillow.

His face lit for a moment, but fell again as he went on.

Betty's face fell open and the General couldn't find anything to say.