What are the characteristics of model operas?

Mainly based on modern themes, the plot will not involve love, and the contradictions between the opposing sides are prominent; Lyrics are easy to understand, compared with traditional drama, there are almost no allusions, straightforward and plain; The vocal design is relatively loud, less euphemistic and feminine; There are no sharp words and no interlayer when singing; Keep the original business, but neither painting faces nor clowns will hook their faces; Changed the original accompaniment in the military and civilian fields and integrated new musical instruments; Prop scenery is more realistic, breaking through the virtual expression of traditional drama.