Sentence examples for old problem from inspiring English sources

This is an old problem.

That's an old problem.

Water contamination is a very old problem.

This solves an old problem of Dixmier.

Old problem -- dangerous new twist.

Ah, yes, that old problem.

Yet old problems remain.

Same old problems.

Interpretations of retrograde amnesia: old problems redux.

Any new solutions to those old problems?

"We can't solve old problems with old solutions.