关于that of的用法that of 算是什么用法?它能引导从句吗?

THAT of ..中THAT是代词,与关系代词无关,它代替了前面的某个内容.
The product in her factory is better than that of mine.
这就要看是啥两个内容在比较呢?是"产品"与"产品"的比较.
We were talking about China and Hongkong's future and that of their patrons.
这个that of 代替了future
．．．
比较就要同质比较,
并行就代替并行的内容.
要符合逻辑