Here's what we learned from last week's airing of Marvel's Agents of S.H.I.E.L.D. - maybe it would be better to air the show at 9 p.m. Eastern/Pacific and 8 p.m. Central/Mountain.Two weeks ago, the show hit its lowest ratings yet. Last week, when that episode was repeated at 7 p.m. MT and a new episode aired at 8 p.m. MT, the new episode ticked up 5 percent. That was still only a bit above the 5 million viewer mark, but it was an improvement.The weird thing is that "S.H.I.E.L.D." has actually gotten a lot better in recent weeks. But the number of viewers last week was about 58 percent smaller than the number of viewers who watched the premiere.By the way, "S.H.I.E.L.D." returns to 7 p.m. (Ch. 4) this week, and Agent Coulson races to save the woman he loves.Elsewhere on TV ...Stanley Cup playoffs: Tampa Bay Lightning at Montreal Canadiens (5 p.m., NHL Network); Boston Bruins at Detroit Red Wings (5:30 p.m., NBCSN); New York Rangers at Philadelphia Flyers (6 p.m., CNBC); San Jose Sharks at Los Angeles Kings (8 p.m., NBCSN)NBA playoffs: Atlanta Hawks at Indiana Pacers (5 p.m., TNT); Brooklyn Nets at Toronto Raptors (5:30 p.m., NBATV); Washington Wizards at Chicago Bulls (7:30 p.m., TNT)The Voice (7 p.m., NBC/Ch. 5): Two contestants are eliminated.Pioneers of Television (7 p.m., PBS/Ch. 7): A look back at TV's doctors and nurses.Glee (7 p.m., Fox/Ch. 13): Rachel makes her Broadway debut.The Originals (7 p.m., CW/Ch. 30): Elijah and Klaus can't agree on how to handle the Crescent Wolves.About a Boy (8 p.m., NBC/Ch. 5): Will invites Sam to a game night hosted by Andy and Laurie.Supernatural (8 p.m., CW/Ch. 30): Sheriff Mills tries to save a girl from a family of vampires.Growing Up Fisher (8:30 p.m., NBC/Ch. 5): Mel tries to prevent Henry from becoming a slacker.The Mindy Project (8:30 p.m., Fox/Ch. 13): Mindy gives the daughter of a cop birth control pills.Celebrity Wife Swap (9 p.m., ABC/Ch. 4): Tichina Arnold and Kelly Packard swap places.Chicago PD (9 p.m., NBC/Ch. 5): The fight betweeen McLeod and Chief Boden intensifies.