Complex sentence: Statistics Denmark has never specified the geographical area of urban Copenhagen, but it is known to consist of Copenhagen Municipality, Frederiksberg and 16 of the 20 municipalities in the old counties Copenhagen and Roskilde, though five of them only partially.
Split into simpler sentences: Statistics Denmark has never specified the geographical area of urban Copenhagen. However, we know it consists of Copenhagen Municipality, Frederiksberg and 16 of the 20 municipalities in the old counties Copenhagen and Roskilde, though five of them only partially.