Related Clues:

• "Mrs. Robinson," e.g
• Outstanding first bit of tart -- a piece for two
• ''The Confrontation,'' in ''Les Miz''
• Two piece?
• It's for two only
• A pair's air
• Owed tenor for music
• "Ebony and Ivory" or "I Got You Babe"
• The Everly Brothers, e.g
• "Ain't No Mountain High Enough" is one
• Sondheim's 'It Takes Two,' e.g
• Something no one can sing?
• Something not done alone, and a hint to the starts of the starred answers
• "Islands in the Stream," e.g
• Number for a pair