Complex sentence: The next year he entered Royal Gymnasium in Křemencová Street, Prague and finished the 6th class and between 1914 and 1915 was again a student of Prague Lesser Town Royal Gymnasium where he took the final exam on June 6,1915.
Split into simpler sentences: The next year he entered Royal Gymnasium on Křemencová Street in Prague and finished the 6th class. Between 1914 and 1915 he was again a student at Prague Lesser Town Royal Gymnasium where he took the final exam on June 6,1915.