CBS has unveiled four new series that it plans to introduce this fall, the sitcom Accidentally on Purpose and dramas NCIS Los Angeles, The Good Wife and Three Rivers . with the changes impacting five nights of the week. The new Jenna Elfman ( Dharma & Greg ) sitcom Accidentally on Purpose is slated to become part of the network's Monday-night comedy bloc. N CIS Los Angeles is scheduled to be paired with the original NCIS on Tuesdays and will be followed by The Good Wife with former E.R. star Julianna Margulies. The medical drama Three Rivers will air on Sundays.