Complex sentence: Reactivated as a Strategic Air Command (SAC) B-29 Superfortress Bombardment Group, Very Heavy, then in 1948 as a Medium Bombardment Group, the group trained in the United States for strategic bombardment operations.
Split into simpler sentences: Reactivated as a Strategic Air Command (SAC) B-29 Superfortress Bombardment Group, Very Heavy, then redesignated in 1948 as a Medium Bombardment Group. The group trained in the United States for strategic bombardment operations.