31.   Air Force officials were not able to say this evening what had caused the crash.

32.   Air safety experts have speculated that propeller problems or ice on the aircraft could have caused the crash.

33.   Airbus spokeswoman Barbara Kracht said it was premature to speculate what could have caused the crash.

34.   Breakages of other fast-moving engine parts have caused several crashes.

35.   But an investigation by the National Transportation Safety Board found that the defective French part caused the crash.

36.   But defense lawyers described a much different company, one in which no one intentionally neglected safety procedures with intent to cause a crash.

37.   But Microsoft critics say that in a well-designed operating system, incorrect data should not cause a crash.

38.   But the only way to keep Boeing in the suit is to maintain that mechanical problems caused the crash.

39.   But the harm will be manageable, analysts said, if the crash was caused by a mechanical problem and not by terrorists.