However, the challenges for many species now seem to be too great.

At that moment, no challenge seemed beyond their combined abilities.

Just three and a half years later, that challenge to the personal computer seems to be at hand.

The unique challenges of this mission didn't seem to affect him.

But the point is that however stiff the challenges seem, we can no longer dodge them.

Seemed to go out of his way to accept challenges, in fact.

But once treatment was available, the challenge seemed to be elsewhere.

The challenge of coaching at Georgetown supposedly no longer seemed to light his fire.

"The challenge seems to be to turn gang members into team members."

Overall, the challenge seems to amount to one clear problem.