Question

求教一个英语句子结构，定语从句？

a series of enzyme-catalyzed processes through which non-nutritional molecules , which are usually hydrophobic(疏水）, are converted into more soluble metabolites.
两个which是什么意思呢？

Answer 1

定语从句得拆开来看，弄清楚谁是先行词和先行词在主句和从句中做什么成分是关键。第二个which的先行词是molecules，也就是which are usually hydrophobic修饰non-nutritional
molecules，也就是non-nutritional
molecules are hydrophobic的意思，既然是修饰，在分析句子时候就可以去掉，所以句子主干其实是a series of enzyme-catalyzed processes through which non-nutritional molecules are converted into more soluble metabolites，through which 的先行词是a series of enzyme-catalyzed processes，相当于先行词在从句中做状语，通过这种a series of enzyme-catalyzed processes方式non-nutritional molecules转化成了more soluble metabolites，希望有帮助！

Answer 2

第一个which是对processes的补充说明，第二个which是对molecules的补充说明。
主干是molecules are converted through processes.

Answer 3

前面的which指的是processes 过程
后面的which指的是molecules分子