Complex sentence: On 12 December 1942, as a counter move, the Germans launched Operation Winter Storm to relieve the 6th Army by attacking through the pincers of the Soviet armies participating in Operation Uranus.
Split into simpler sentences: On 12 December 1942, as a counter move, the Germans launched Operation Winter Storm. The Germans launched Operation Winter Storm to relieve the 6th Army by attacking through the pincers of the Soviet armies participating in Operation Uranus.