Complex sentence: Commander Carrier Strike Group Twelve (COMCARSTRKGRU 12 or CCSG 12) exercises oversight of unit-level training, integrated training, and readiness for assigned ships and units, as well as maintains administrative functions and material readiness tracking for ships and squadrons assigned to the group.
Split into simpler sentences: Commander Carrier Strike Group Twelve (COMCARSTRKGRU 12 or CCSG 12) is the command authority for Carrier Strike Group Twelve. This flag officer is responsible for unit-level training, integrated training, and material readiness for the ships and aviation squadrons assigned to the group.