I had a difficult time concentrating on what Daddy had to say.

But she had a hard time concentrating on the notes.

Guys had a hard time concentrating on getting in shape.

He looked at the photographs again, this time concentrating on the mountains.

Maybe that's why I had a hard time concentrating on my essay.

From 1988, the focus returned to collecting prints, this time concentrating on the 20th century.

But I was having a hell of a time concentrating.

Her thoughts remained fuzzy, and she had a difficult time concentrating on details.

Last night had only been a start, and he'd had a hard time concentrating on anything but Sophie all day long.

Lloyd apparently had a difficult time concentrating on his studies.