I'm impressed you could keep concentrating on that kind of problem at a time like this.
Concentrate on ordinary things; deal with all of this a little at a time.
He said he would rather concentrate on one thing at a time, not wanting to compromise the quality of his work, school or film.
"We really have to concentrate on one thing at a time in terms of legislative effort."
The humans concentrated theirs against a single adversary at a time.
When she looked again, she held herself steady by concentrating on one or two Images at a time.
She concentrated on a single thing at a time.
How can I get them doing any more interesting work if they can't concentrate for more than ten minutes at a time?
Better, she decided, to concentrate on one friend's problems at a time.
But I think the problem is that you you only concentrate on little bits at a time.