One of the million complications of thinking about this lecture is indeed to what extent it really is a significant departure from the work of structuralism.
1. is 是系动词,indeed 是副词修饰 is,“的确是”。
2. to what extent it really is a significant departure from the work of structuralism,是表语从句,结构上是名词性特殊疑问分句。也就是说,这个表语从句本身又是一个间接的特殊疑问句,由于做了名词性从句,故取名为 “名词性特殊疑问分句”。名称无所谓,你知道它是表语从句,由 what 引导,介词 to 提前就行了。
3. 特殊疑问句的例子:
To what extent are you willing to help me? 你愿意在多大程度上帮助我?
To what extent does she rely on you? 她在多大程度上依赖你?