Complex sentence: In the summer of 2010 Sainsburys opened its new store on the former Ushers site, its currently the only part of the site to have been developed, the other part remaining derelict.
Split into simpler sentences: In the summer of 2010 Sainsburys opened its new store on the former Ushers site. It is currently the only part of the site to have been developed, the other part remaining derelict.