1.   I have to think of things for him to do to challenge him.

2.   In interviews, doctors said that the new rates affected how they do business, with economics challenging lessons learned in medical school.

3.   Three loud cheers for American sportswear and all it has done to challenge the attitudes that inhibited the male wardrobe.

4.   Now others are hitting the quad more regularly, so what does Yagudin do to challenge that?

5.   Damon Hill of Britain was forced off the track in the start shunt but came back after five laps with too much to do to challenge the leaders.

6.   Though he was lapping faster than anyone else, he had too much to do to challenge the leaders.