Complex sentence: The upper level of the centre was laid on 6 May 2008 which was a distinctive gull-wing shaped steel and glass roof over the central courtyard was installed around the end of August 2008.
Split into simpler sentences: The upper level of the centre was laid on 6 May 2008. A distinctive gull-wing shaped steel and glass roof over the central courtyard was installed around the end of August 2008.