The snow on 13 and 15 December covered these defensive positions, camouflaging them so they blended with the terrain.
(The snow on 13 and 15; covered; these defensive positions; T:December) (The snow on 13 and 15; camouflaging; them) (they; blended; with the terrain)
The snow on 13 and 15 The snow on 13 and 15 they
covered camouflaging blended
these defensive positions T:December
them
with the terrain