Complex sentence: The 10 P.M. newscast did not face competition until March 5,2007 when WUPV launched a 35-minute weeknight newscast produced by WTVR.
Split into simpler sentences: The 10 P.M. newscast did not face competition until March 5,2007. On that date, WUPV launched a 35-minute weeknight newscast produced by WTVR.