Complex sentence: Johnson-Thompson competed for Great Britain at the 2012 Summer Olympics in the women's heptathlon alongside compatriots Jessica Ennis and Louise Hazel at the Olympic Stadium on 3--4 August.
Split into simpler sentences: Johnson-Thompson was selected to compete for Great Britain at the 2012 Summer Olympics in the women's heptathlon alongside compatriots Jessica Ennis and Louise Hazel. The event will be held at the Olympic Stadium on 3--4 August.