学生疑问：老师，这句话句子成分找不明白：Add the fact that food is full of hundreds of bioactive compounds, each of which varies depending on where plants are grown or animals are raised, and you've got quite a lot of information to puzzle out.

老师答疑：主干就是and连接两个句子并列，“祈使句+and +陈述句”。祈使句：Add the fact that...are raised，陈述句：you’ve got quite a lot of information to puzzle out. that ...are raised是fact的同位语从句，同位语从句中又有which定语从句修饰compounds和where...引导介词 on的宾语从句。and you’ve got quite a lot of information to puzzle out就是另外一个句子。

分析点评：长难句确定句子主干时，先识别并暂时忽略句子中的修饰成分（这些成分不参与主干构成，去掉后不影响句子核心意思）。