Which opera, if any,  Venus and Adonis or Bluebeard's Castle has more acts ?
Bluebeard's Castle Bluebeard's Castle (Hungarian: A kékszakállú herceg vára ; literally: "The Blue-Bearded Duke's Castle") is a one-act opera by Hungarian composer Béla Bartók. The libretto was written by Béla Balázs, a poet and friend of the composer, and is written in Hungarian, based on the French literary tale "La Barbe bleue" by Charles Perrault. The opera lasts only a little over an hour and there are only two singing characters onstage: Bluebeard ("Kékszakállú "), and his new wife Judith ("Judit " ); the two have just eloped and Judith is coming home to Bluebeard's castle for the first time.
The Emerald Isle The Emerald Isle; "or, The Caves of Carrig-Cleena", is a two-act comic opera, with music by Arthur Sullivan and Edward German, and a libretto by Basil Hood. The plot concerns the efforts of an Irish patriot to resist the oppressive "re-education" programme of the English, which has robbed the Irish of their cultural heritage. A quirky "Professor of Elocution" who is hired by the English to continue this "re-education" of the Irish switches sides to help the Irish. Romantic complications cause a confrontation between the Irish patriots and the superstitious English at the supposedly haunted caves of Carric-Cleena, and disguises are employed to hold the English off; but the professor ultimately comes up with a solution that works out happily for all.