I'd been involved in that plane near miss on the way to York which would have frightened anyone and it was hard to concentrate properly.
Others might have found that the drug made it too difficult to concentrate properly, but Peterson did not seem to experience such a hindrance.
In fact, there were too many of them for him to concentrate properly on his exercises.
Just give me enough time now to concentrate properly.
They do not understand that he cannot properly concentrate and chitchat at the same time.
Both Red and Blue were now too busy to concentrate properly on each other.
But I would not have been able to concentrate properly on my own game.
It wasn't only that fear kept her from concentrating properly.
"Maybe I've been thinking too much about other situations to concentrate properly."
I can tune that out without a problem but if there's music on I can't concentrate properly.