Assertion: classical music's opera | /r/HasProperty | number opera
Facets:
value: often
type: TEMPORAL
Source sentences:
text: Traditional opera, often referred to as "number opera", consists of two modes of singing: recitative, the plot-driving passages sung in a style designed to imitate and emphasize the inflections of speech, and aria (an "air" or formal song) in which the characters express their emotions in a more structured melodic style.