说维多利亚女王的.

说维多利亚女王的.
Neither she nor anyone else has ever seen anything like this building before .A green house ,the size of a palace with a difference that this is from the beginning ,a people's place .A popular magazine calls it the Crystal Palace .Its grandeur spaces are filled not with courtiers and flunkies ,but steam pumps and locomotives ,a huge showcase for britain's industial empire .Just 3 years before ,in 1848 ,Europe had been torn apart by revolutions .The government had feared the same would happen here.这段话中其中有一句A green house ,the size of a palace with a difference that this is from the beginning ,a people's place .
这里的为什么要有个this,这个that引导的是一个什么从句.