Skeeter's whole concentration narrowed to Lupus Mortiferus and his flashing swords and grinning face.

Alberich's concentration narrowed to a few, vital tasks.

His concentration narrowed until all he was aware of was the sound of his own breathing, and the opponent in front of him.

Nicholas' concentration narrowed as he slewed into the dimly lit locker room.

He cursed, and his concentration narrowed.

The flame wavered and he stopped laughing; his concentration narrowed to a point again.

Warren's concentration narrowed to an absolute problem that took in the Swarmer and its circling and the closed geometry of the raft.

"And another behind that" His concentration narrowed on the task at hand, and he didn't take the time to sort out the whispers he heard all around him.

His concentration narrowed to the dusty circle, Orain's eyes, and the sword in his own hands.