He seemed to be struggling to keep a smile off his face.

He was trying hard to keep the smile off his face.

It was difficult to keep a look of triumph off his face.

This time, he couldn't keep the smile off his face.

I kept my eyes off his face in case he needed some privacy.

I looked at him and couldn't keep the surprise off my face.

I stared up at Richard and couldn't keep the fear off my face.

I have no idea how she kept a smile off her face.

I worked very hard at keeping the surprise off my face.

Now the American could not keep the smile off his face.