Darkness is quite unnecessary, but I think it helps one to concentrate.'

The narrowness serves to concentrate the strength and accelerate the work.

But London thwarted her; in its atmosphere she could not concentrate.

She shook her head, tried to concentrate her attention, and failed.

He answered: "You're a clever little woman, but my motto's Concentrate."

It took me two and I had to concentrate my thought by main strength even then.

When Mamie is around I cannot seem to concentrate on my playing.

Naturally, then, our play is to concentrate everything on getting it granted.

The business had been expanding; they would now "concentrate."

Just a single unrelated fact that I used with others to concentrate on.