非限定性定语从句能转化成分词短语的句子吗?

首先你说的应该是过去分词短语吧.被动语态的定语从句一般可以转换为分词短语作定语.如：
I met the boy who is named Tom.
I met the boy named Tom.
非限制性定语从句也是可以的,少.多半被看作是状语了.
Mr Smith,who was praised by the leader,was very happy.
Mr Smith,praised by the leader,was very happy.其实也就是：Praised by the leader,Mr Smith was very happy.

被动语态的定语从句可以转换为分词短语作定语