How the genes control these changes is a central problem.

I'm sure he can but I don't believe that is the central problem.

But wasn't that the central problem of this whole project?

The central problem, so it seemed, was to learn from whose eye he looked forth.

How to get fathers more time at home remains the central problem.

But the central problem remains that of cost to the customer.

That had been the central problem in his life too.

For this, he could now see, was the central problem of human beings.

We can point to central problems of values, structure, and behavior.

But you're still left with the central problem of having a live event, which theater is, on screen.