Complex sentence: The Murano was announced in 2005 when Philadelphia, Pennsylvania was experiencing a condominium boom that had begun in the late 1990s; between 1998 and 2004 more than 70 Center City office and manufacturing buildings had been converted into rental and condominium apartments.
Split into simpler sentences: The Murano was announced in 2005 when Philadelphia, Pennsylvania was experiencing a condominium boom that had begun in the late 1990s. Between 1998 and 2004 more than 70 Center City office and manufacturing buildings had been converted into rental and condominium apartments.