many of our dreams__impossible in the past have come true （a)were considered （b)considered为什么不选A呢

答案是B.因为__impossible in the past 这一部分是many of our dreams的定语，动词作定语时要么用定语从句，要么用-ing分词或--ed分词。如果用A的话，要加上关系代词which或that构成定语从句，因为关系代词作主语不能省去。所以用选B，consider和many of our dreams存在被动关系，用-ed 分词作定语。

因为“__impossible in the past ”这是一个分词作主语补足语，这里的considered 不是真正的谓语，句子真正的谓语是have come ture

many of our dreams__impossible in the past have come true a)were considered （b)considered这是一个非谓语的考点在这道题中have是这个句子的谓语一个句子只能有一个谓语梦想被认为是不可能实现的所以选B过去分...

是这样的：
considered impossible in the past 是过去分词短语作后置定语，限定dreams