The room, although to be kept locked, was often left open.
A. supposing
B. supposed
C. to be supposed
D. having supposed
网友回答
A. supposing
(答案→)B. supposed
C. to be supposed
D. having supposed
解析：考查状语从句的省略：句意：这个房间虽然应该一直锁着，但总是开着。完整的句子是：The room, although it is supposed to be kept locked, was often left open.当主从句的主语一致的时候，可以省略从句的主语和be动词，选B。