Question

老师你好，请教一个英语语法问题

A hypothesis is falsifiable if there exists a logically possible observation statement or set of observation statements that are inconsistent with it, that is which, if established as true, would falsify the hypothesis.
其中， that is which，that的语法功能，which的语法功能。

Answer 1

这是多重复合句

【第一重】

• 主句：A hypothesis is falsifiable 假设是可以被检验的

• 条件从句：if there exists a logically possible observation statement or set of observation statements that areinconsistent with it, that is which, if established as true, would falsify the hypothesis.

【第二重（嵌套在条件从句中）】

• 主句：there exists a logically possible observationstatement or set of observation statements （如果）在理论上存在一个或一组观察数据陈述

• 定语从句：that are inconsistent with it, that is which, if established as true, would falsify the hypothesis. <that 是关系代词，指代前文的“一个或一组观察数据陈述>

【第三重（嵌套在定语从句中）】

• 插入性条件从句：if established as true 如果它们被确定是真实的 <= it or they are establishedas true >

• 主句：that are inconsistent with it  这种观察数据陈述与假设前后矛盾

• 同位语：that is which would falsify the hypothesis  也就是说这种观察数据陈述歪曲了假设 <that is 相当于 that is to say、 namely、in other words >.

追问

请问老师，在第三重中，which 如何理解其语法功能？