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.