Never before in the history of music have musical superstars been able to command so extraordinary fees of the kind they do today.

(A) so extraordinary fees of the kind they do today

(B) so extraordinary fees as they are today

(C) such extraordinary fees as they do today

(D) such extraordinary fees of the kind today’s have（C）

(E) so extraordinary a fee of the kind they can today

1）关于so和such可以理解成so修饰extraordinary，即和以前比现在的fees so extraordinary，也可以理解成such修饰中心名词fees，我不明白第一种理解为什么不对

2）这句正过来是不是应该是no superstars have been able to command so extraordinary fees as they (are able to command) today. 那么as后应该用they are, 为什么答案用they do?

thanks

仍然不理解为什么要用do，而不能用are，代替are able to...

请牛大人指教！！