No matter how frequently they are performed, the works of Beethoven still attract people all over the world. 不管被表演了多少遍，贝多芬的作品依然能吸引全世界的听众。
此句中的No matter how frequently they are performed是让步状语从句吧，请问其中的they are可以省略吗？因为许多状语从句，当主语与从句主语相同，且从句谓语动词含有动词be时，是可以省略从句主语和动词be的。谢谢老师解答！