Parallel intervals of a fifth, octave or unison are traditionally prohibited in four-part writing.

五度，八度或一度音程平行传统上在四声部作品中禁用。

youdao

Parallel intervals of a fifth, octave or unison are traditionally prohibited in four-part writing.

五度，八度或一度音程平行传统上在四声部作品中禁用。

youdao