The concert began with a piece by an undnown composer.
问题描述：
The concert began with a piece by an undnown composer.
这句话里,a piece的意思我不太懂,我对它的理解是a piece指代的是一首曲子,完整的结构是:a piece of music,它省略了"乐曲",是不是这样?
答
这句省略了a piece [of music created ]
音乐会以一首由一位不知名作曲家创作的乐曲拉开了序幕.