21.   Mercury Energy spokeswoman Diane Miller said she thought the fault occurred in a joint in the cable but engineers were working to determine the exact cause of the failure.

22.   National Transportation Safety Board Chairman James Hall attended the service and said his agency was working to determine the cause of the crash.

23.   Officials were still working to determine the weight of those board.

24.   Police experts were working to determine when the theft took place.

25.   Scientists are working to determine what causes the storms and what implications they might have.

26.   Scientists were still measuring the size of the earthquake and working to determine its epicenter.

27.   Sato said officials were working to determine why the latest outbreak occurred and added that contaminated school lunches were considered a possible cause.

28.   Technicians were working to determine what went wrong.

29.   There were reports of heavy fog in the area, and investigators were working to determine the exact cause.

30.   Velez said investigators were still working to determine what caused the plane to crash in an isolated corner of the mountainous Cerro Negro region.