Task: Question Generation
Input (English): The Sarah Jane Adventures, starring Elisabeth Sladen who reprised her role as investigative journalist Sarah Jane Smith, was developed by CBBC; a special aired on New Year's Day 2007 and a full series began on 24 September 2007. A second series followed in 2008, notable for (as noted above) featuring the return of Brigadier Lethbridge-Stewart. A third in 2009 featured a crossover appearance from the main show by David Tennant as the Tenth Doctor. In 2010, a further such appearance featured Matt Smith as the Eleventh Doctor alongside former companion actress Katy Manning reprising her role as Jo Grant. A final, three-story fifth series was transmitted in autumn 2011 – uncompleted due to the death of Elisabeth Sladen in early 2011.
Output (English): Why did the series end in 2011?