The man was concentrating his entire attention on the men below him.

But the men did not look to the east; both concentrated on the zenith.

But the man was concentrating on changing lanes and didn't hear her.

Rain said, the small man concentrating as if trying to remember something.

Both men were concentrating intently on a playing board set between them.

Every man must have been concentrating on his own survival.

It was a goal every man had concentrated on for months.

"Have you ever seen a man concentrate the sun with a lens to make something catch fire?"

How can a man concentrate his mind with all this noise?

The man could not concentrate his deadly gaze on anything at the moment.