It's only gone to a higher and more visible level twice in the last three years, during some unusually difficult cases of his.

At the same time, it is only fair to point out that my task in this instance had been of an unusually difficult order.

Others have applied to graduate and professional schools, making admission unusually difficult over the last year.

When a kid is having an unusually difficult time in school, then it is useful to try to figure out what's going on.

But California has some unusually difficult enrollment and financing problems.

The emphasis on defense makes the position unusually difficult to fill.

Both companies faced an unusually difficult regulatory battle just to start operations.

But even without such a crisis, the European Union is facing unusually difficult months.

So the situation is unusually difficult to understand, let alone manage.

The last few years were unusually difficult for Nelson, who turned 65 on Sunday.