问题补充:
Many things impossible in the past are quite common today.
A. having being considered
B. considered
C. are considered
D. considering
答案:
A. having being considered
(答案→)B. considered
C. are considered
D. considering
解析:句意:很多在过去被认为是不可能事情在今天很常见。此空位于things后,与things之间是被动关系,故用过去分词做定语。having being considered 用做状语,不做定语,故排除A。are considered 是谓语动词形式,故排除C;considering是现在分词表示主动,故排除D。故选B。