11.   But Ryan said the purpose of the report is not to find a culprit, but to prevent future tragedies.

12.   But not even the most stringent rules on the books can always prevent a tragedy in the ring.

13.   But not many clapped when Clinton called for meaningful action to prevent similar tragedies in the future.

14.   But Welsh said diligence in checking the background of day-care providers can help prevent such tragedies.

15.   By sharing their story, Nancy and Kenneth Stevens hope to help parents prevent similar tragedies.

16.   But Worcester prosecutors say Barnes and Levesque could have prevented the tragedy, had they behaved differently.

17.   Dillon believes similar American tragedies can be prevented through tougher policing of fishing.

18.   Doctors have learned that, to prevent tragedies, children with even mild asthma need medication.

19.   Dr. Alvin Ponder, a neighbor who witnessed the rescue and treated Whaley after he escaped, said the firefighter had prevented a tragedy.

20.   Following the Oklahoma City bombing, law-enforcement officials have complained privately that those guidelines hamper them from gathering the kind of information needed to prevent such tragedies.