Question

请帮我解释一下这到外语题。谢谢！！！

Many things ____impossible in the past are common today.
A)considered B)to consider C)considering D)to be considered

Answer 1

A
Many things (which were) considered impossible in the past are
common today.
括号中为省略部分
许多过去被认为不可能的事情在今天已经司空见惯了。
首先是被动，被认为，排除B，C
其次是过去被认为，排除D，D表示将来
所以选A

Answer 2

A
considered为动词的过去分词做后置定语修饰前面的things，表示被动，在过去很多被认为不可能的事情在今天已经很平常了。

Answer 3

选A

Many things (which were) considered （to be）impossible in the past are
common today.
括号中的是省略了的部分 。

consider sth. to be sth./形容词 意思是"认为...怎么样"，其中to be 可省略。
而句中were considered to be意思是“被认为怎么怎么样”