This is quite a challenging assignment, but you'll find it worth the effort.

Perhaps the most challenging assignment of all has been learning aggressive street reporting.

The giant ensemble was one of their most challenging assignments.

Another was reluctant to take a risky and challenging assignment.

This wasn't the most intellectually challenging assignment, but it had turned out to be one of the more interesting ones.

He was going north, to a new and challenging assignment.

The A's are given more challenging assignments and disproportionate nurturing.

An officer, during his career, serves in many challenging assignments.

Democracy is a highly challenging assignment, which allows a person great freedom.

"Referring to a toilet bowl is certainly a challenging assignment," he said.