The challenge for anyone in show business is keeping a career afloat after the public's attention has moved elsewhere.

And with 4 levels of difficulty, new challenges will keep you coming back for more.

The challenge will keep them from asking any other ships for help.

My mother has said "the biggest challenge was keeping David busy".

But the challenge, he said, will be keeping them away from human predators.

The challenge for elevator companies, he added, is keeping it that way.

Even parents can't keep from playing (the challenge is keeping them in the designated play area).

A challenge is keeping the food warm and ready at each location.

"I do feel like a new challenge can keep you young."

This means great complexity and an organizational challenge to keep track of everything.