题目内容：

The biggest room is this building_____used as .A.is used to be B.is used to C.used to D.used to

优质解答

应该是 used to be 因为是做后置定语 修饰 this building A 错在多用了系动词 与前面的is 矛盾
B错 C和D 怎么答案一样啊