Getting her to open up was turning out to be one of his toughest assignments.

What a lot of work it all was, but on a tough assignment they shot for extra credit.

Field trips in the 1920s and 1930s were tough assignments.

There can't have been many tougher assignments in recent British political history.

But it was the staff that got the tough assignments.

He has had some tough defensive assignments and came through.

You ought to do just fine, even though this is going to be a tough assignment.

In fact, it is one of the toughest assignments on the street.

But they also say he received some of the toughest assignments.

Anybody could tell that this was going to be a tough assignment, if not an impossible one.