"Aren't they supposed to prevent things like this from happening?"

Perhaps the book helped to prevent things from getting even worse.

But he was in the business of preventing such things.

This wouldn't prevent things going wrong or not working, but it would at least cut down the odds.

So it's our task to prevent things from going that way.

We will prevent such things from happening in the future.

"We must work out ways to prevent and avoid such things, having in mind their foreign policy aspects as well," he said.

This is particularly important to prevent such things from happening again.

The answer may well be yes, he said, adding that the changes over the last four years "won't prevent things."

"It's much better to prevent things than to have to try to fix them."