1.   Although the first five previews had to be cancelled because of mechanical difficulties with the set, the troupe is keeping its cool.

2.   A small percentage had irritation or skin problems at the insertion site, or mechanical difficulties with the implant.

3.   But weather, air traffic, mechanical difficulties, rules governing crew hours and hundreds of other causes, including human error, can upset schedules.

4.   Crashes that begin in the cruise phase of flight are very rare, as are mechanical difficulties that cannot be overcome.

5.   He was sent down to work out some mechanical difficulties.

6.   It immediately ran into mechanical difficulties.

7.   On Friday, as the buses snaked through the mountains of central Oregon, mechanical difficulties and logistical problems left the caravan running hours behind schedule.

8.   She often tried to urinate standing up, despite the mechanical difficulties.

9.   The third plane, carrying two players and eight support personnel, suffered mechanical difficulty and crashed in an open field near Byers, Colo.

10.   U.S. and Colombian officials investigating the crash have ruled out sabotage and mechanical difficulties.