The toughest obstacle, he said, is having people acknowledge that they are criminals.

They soon discovered that their toughest obstacle was finding money for the program.

Even as we speak, they are here in New York for a go at a tough obstacle, the American wine market.

The door was a tough obstacle, but it gave.

And that had proved to be a tough obstacle indeed.

"There are some tough physical, logistical obstacles to recycling," he said.

Sometimes in life you have to get through certain things, and there are tough obstacles to overcome.

If the team knew I was up and about, I would have much tougher obstacles.

With a little leisure to study the problem he would think of something; he had beaten tougher obstacles than this one in the past.

He creates tough obstacles for Batman and the others until after he is out of the race.