This problem is very difficult.

He was taking it easy from the start of the game itself.

The problem itself is not difficult.

Can you answer this question?

In philosophy, the thing-in-itself is considered an absolute existence that we cannot recognize.

No problem, I will do that job.

That proposal is completely unthinkable.

As a practical question, how are we going to fund this project?

This exam is a matter of life or death for me.

He is viewing that situation as a serious problem.