1.  Cars seem to be the most difficult thing to purchase on a cash basis.

2.  The most difficult thing afoot is to keep our problem child from blowing it in one fell swoop.

3.  The most difficult thing for Brown was defending a policy in public that he opposed in private.

4.  There are difficult things going on here.

5.  To be a parent is a terribly difficult thing.

6.  I have a fair idea of how difficult things can be.

7.  The most difficult thing in a fast game of rugby is to change course midstream.

8.  To adjust the concept of time is the most difficult thing.

9.  They are also the most difficult things to maintain in any society.

10.  Patrick thought that telling Midge the bodies were not those of John and Angela would be the most difficult thing.