sentences:  The XXI Bomber Command was assigned the task of destroying the aircraft industry of Japan in a series of high-altitude, daylight precision attacks
  
  In late October and early November 1944, a series of tactical raids were carried out as training exercises for the crews.From Saipan, the groups of the 73d Bomb Wing flew several bombing missions against Truk to gain combat experience.Aware that there was now a new threat, Japanese aircraft based on Iwo Jima staged a low-level raid on Isely Field on 2 November, damaging several B-29s on the ground.