As part of the battle of Moscow, the battle was quite large. There were four battles in Liezhev-vyazma, the first one was 1 (42 years, 1 to April), the Soviet army lost 770,000, the second one was 1 10,000 (July to August), and the third one was110,000 (Mars campaign). If Rostov or Ji gives up one, or Viazhma and Liezhev attack one, the problem of annihilating an army group should not be great, and the quality of the Soviet army is poor, so that the war will never fall to the Soviet Union in time.
As for the lack of sufficient reserves, I personally think that the Soviet Union should be able to give the Germans a heavy blow and eat an army, but the central line will not collapse, but without reserves, I am afraid that the central line will be lost and Mo Deer will be finished. As for the transfer of troops to Stalingrad, I personally think it is very difficult.