你好,本句是被动语态.
用了现在完成时的被动语态
have been cancelled
意思是：很遗憾音乐会被取消了.
如果have / has been 后面有过去分词,就是被动语态
如果have / has been 后面没有过去分词,就不是被动语态
例如：
He has been in Beijing for ten days.
这一句就不是被动语态.