The most insignificant of Strickland’s works suggests a personality which is strange, tormented, and complex; 

and it is this surely which prevents even those who do not like his pictures 

from being indifferent to them; it is this which has excited so curious an interest in his life and character.

上面句子中，出现了it is this surely which...和it is this which...请教老师，这是一种什么样的句式？ 我感觉有点类似于强调句。

麻烦老师分析一下，谢谢！