You could tell he was trying to concentrate and all.

After a while, he gave up trying to talk, and tried to concentrate on what had happened.

Trying to concentrate because they had to hear it right, good or bad.

He tried to concentrate on them rather than anything else.

She tried to concentrate on what the young man was saying.

I went away, and tried to concentrate upon my work for the next few days.

I was trying very hard to concentrate on the game.

I was just trying to concentrate on one out at a time.

She put her back to them, to make sure, and tried to concentrate on the room.

He sat down with the list and tried to concentrate.