1996年阅读第二篇最后一句话的疑问

But it is the arrival of new satellite channels-funded partly by advertising and partly by viewers' subscriptions-which will bring about the biggest changes in the long term.
这句中的it is ...which 到底是不是强调句型？看好多语法介绍上面，强调句型里都没有这一种，都是用that 或者who的。

我感觉不像强调句

我看新东方范猛讲的阅读，说这是一个强调句。