这里that 是adj吗？如何理解跟在后面的动名词短语？

This construction is not sharply distinct from that containing a noun postmodified by a non-wh relative clause

     【答】that containing a noun postmodified by a non-wh relative clause = the construction containing a noun postmodified by a non-wh relative clause

划线部分是现在分词短语作后置定语。