Н51
КАК НЁБО ОТ ЗЕМЛИ отличаться
coll (как +
NPInvaradvfixed WO (to differ) very much, sharply
X отличается от Y-a как небо от земли = X and Y are as different as heaven and earth (as night and day )
X is the exact (the very) opposite of YX is poles apart from YX and Y are poles (worlds) apart.