It's been about these families and the challenges they face every day of their lives.

Tonight, I want to speak to you about the challenges we all face as a people.

But like many of you, I am concerned about the challenges now before us.

We have already heard about possible challenges to the results in the courts.

The book is about teen love problems and the challenges of growing up.

Ask other public officials and leaders to talk about the challenges in the response to the epidemic.

Think about the challenges of teaching math to children on a computer at home.

MS patients in their 30s talk about the challenges of coming out with the disease.

But she is serious about the challenges confronting the bank.

On the next page, you'll read about the challenges astronauts face as they return home.