"But the way they're going about it could be a costly mistake."

And in some cases, he said, failure to do so can be a costly mistake.

We made a few costly mistakes and they got us.

That was a costly mistake; a dog would have gone the other way.

The enemy then began a series of very costly mistakes.

"It could have been a very costly mistake," he said.

"The Moscow group decided that they would show everybody the right way to be democratic, but it was a costly mistake."

It's all too clear what a costly mistake it was for the President not to have claimed this ground from the start.

But if he didn't take the time, there might be costly mistakes.

But some costly mistakes cost him his starting job last season and led to this season's loan deal.