41.   He had been ill, but the exact cause of death was unclear, said his wife, Catherine.

42.   He ran home from school to tell his mother, although he was a little confused about the exact cause for the excitement.

43.   He said the exact cause of the defect is unknown.

44.   His New York agent, John Hawkins, said the exact cause of death awaited further tests.

45.   His secretary, Pat Martin, said she did not know the exact cause of death.

46.   However, the exact cause of the generating plant failure is not known.

47.   However, determining the exact cause of the deaths may be complicated by the very fact that all three apparently were used to taking strong doses of narcotics.

48.   Investigators have yet to determine the exact cause, but some fire officials said the fire might have started in a wastebasket in the gift shop and smoldered overnight.

49.   Investigators probably will never know the exact cause of the smoke or fire reported on the craft, Rapoport said.

50.   Its exact causes are unclear.