Two had tried to return, to challenge their mother on her own ground.

A few simply see a chance to challenge the President on a foreign policy issue.

If they challenge us on this, we can explain it.

He knew better than to challenge her on a minor point.

I'm never challenged on the street to see how tough I am.

He was challenged again tonight on the point in the debate.

So does the fact that he is not trying to challenge a competitive world on his own.

"But he felt it was time, and I certainly wouldn't challenge him on that."

I'm the type of guy, I'll challenge you on anything.

He was being challenged on too many sides at once.