Which opera, if any,  Venus and Adonis or Bluebeard's Castle has more acts ?
Venus and Adonis (opera) Venus and Adonis is an opera in three acts and a prologue by the English Baroque composer John Blow, composed in about 1683. It was written for the court of King Charles II at either London or Windsor. It is considered by some to be either a semi-opera or a masque, but "The New Grove" names it as the earliest known English opera.
Bluebeard (ballet) Barbe-bleue (en. "Bluebeard") (ru. «Синяя борода», "Sinjaja boroda") is a "ballet-féerie" in three acts and seven scenes, originally choreographed by Marius Petipa to the music of Pyotr Schenk. The libretto was created by the author and dramatist Countess Lydia Pashkova from the fairy tale "Bluebeard" by Charles Perrault. The ballet was first presented by the Imperial Ballet on December 20 [O.S. December 8] 1896 at the Imperial Mariinsky Theatre in St. Petersburg, Russia, the first performance being a benefit in honor of Marius Petipa's fiftieth anniversary in service to the St. Petersburg Imperial Theatres.