一个考研英译汉的句子But even more important,it was the farthest that s

一个考研英译汉的句子
But even more important,it was the farthest that scientists had been able to look into the past,for what they were seeing were the patterns and structures that existed 15 billion years ago.其中it was the farthest that scientists had been able to look into the past这句话,有的人说it was the farthest是主句,that引导的是定语从句.还有的人说it was that是强调句,the farthest做状语,还原就是look the farthest into the past.我个人认为这句话是强调句,但the farthest是名词,做look的宾语.我真的不是很明白,
强调的是什么成分呢?还原回去是什么样子呢?