it was planted where its tough roots which grow up to five feet long could help hold back the soil
问题描述：
it was planted where its tough roots which grow up to five feet long could help hold back the soil
意思能理解,但是它的构造是怎么回事呀?
答
which grow up to five feet long 定语从句修饰先行词 roots
where its tough roots could help hold back the soil 状语 从句的主句部分,
整句话的主句it was planted