11.   An investigation has failed to discover the cause of an epidemic which struck more than sixty people and closed a school.

12.   An investigation has failed to discover the cause of an epidemic which struck more than sixty people.

13.   SCIENTISTS are one step closer to discovering the cause of cot death syndrome which kills hundreds of babies each year.

14.   SCIENTISTS believe they are one step nearer to discovering the cause of Cot Death Syndrome, which kills hundreds of babies every year.

15.   Fire brigade investigators are still trying to discover the cause of the explosion and any chain of events which might have led up to it.

16.   Corpoven officials said a full investigation will be launched to discover the cause of the blast.

17.   Despite intensive searching, no actual cause was discovered.

18.   Federal investigators have yet to discover the cause.

19.   However, the primary responsibility for discovering causes of the accident, and making sure that construction can safely proceed, lies with New York City.

20.   In World War II, as senior organic chemist with what is now Exxon, she discovered the cause of deposits affecting superchargers of aircraft engines.