Complex sentence: The Opening Ceremony was held at the QEII Stadium (named for Queen Elizabeth II), in the Brisbane suburb of Nathan, was also the venue which was used for the athletics and archery competitions during the Games.
Split into simpler sentences: The Opening Ceremony was held at the QEII Stadium (named for Queen Elizabeth II), in the Brisbane suburb of Nathan. The QEII Stadium was also the venue which was used for the athletics and archery competitions during the Games.