Complex sentence: The front line was held in the immediate vicinity of the plant, which was subjected to heavy enemy shelling-by 1944, only 327 of Kolpino's 2183 houses remained intact.
Split into simpler sentences: The front line was held in the immediate vicinity of the plant, which was subjected to heavy enemy shelling. By 1944, only 327 of Kolpino's 2183 houses remained intact.