"So You Think You Can Dance" (8 p.m., Fox): You can cut the tension with a knife as crunch time

"So You Think You Can Dance" (8 p.m., Fox): You can cut the tension with a knife as crunch time nears. This episode has the top 12 contestants strutting their stuff in hopes of wowing the judges -- and you.
"Modern Marvels" (9 p.m., History Channel): A new episode called "Writing America" takes a look at three inventions that transformed the nation -- the telegraph, the telephone and the electric light.
"Hard Rock Live" (8 p.m., MTV): My Chemical Romance performs introspective tunes for an audience in Orlando, Fla. If it's the early-bird-special crowd, the band might have a problem on its hands.
"American Masters presents Willa Cather: The Road Is All" (10 p.m., PBS): Willa Cather's spirited novels -- "O Pioneer," "My Antonia," "One of Ours" -- paint vivid pictures of the Nebraska prairies, but the details of her own life remain a mystery. A private person, Cather destroyed much of her correspondence. Yet her independence became an inspiration to women.
This new documentary, filmed in widescreen high definition technology, looks at Cather and her literary work. Marcia Gay Harden provides the voice of Cather.