Sentence examples for a difficult problem to crack from inspiring English sources

I'm sorry for our supporters but we've tried almost everything and are finding it a difficult problem to crack.

Reliably forecasting the timing, location, and magnitude of an earthquake has been a difficult problem to crack.

This can be a particularly difficult problem to crack because, while overconfidence can dissuade us from spending enough time or money on acquiring more information or doing extra analysis, just acquiring more information can make matters worse by adding to the sense of confidence.

"The big, looming, difficult problem to crack is the general adult population and the millions of people with multiple partners and overlapping relationships.

It is a difficult problem to solve.

It seems like a difficult problem to me.

"It's a difficult problem to quantify".

It's a difficult problem to solve.

Sexual harassment is a difficult problem to study.

It's a difficult problem to solve on your own.

The reason for that is that firstly search is a hard, expensive problem to crack.