关于英语定语从句The trees that they planted grow very well.为什么that做宾

我来试试看：这是有定语从句的句子。我试着分解如下：They planted the trees。The trees grow very well。把两句合并起来：The trees that they planted grow very well。"that"="trees" 引导定语从句,又是从句中planted的宾语。这个”that"也可以用“which",引导词在从句中做宾语也可以省略。The trees they planted grow very well。另外：The tallest tree (that) they planted grow very well。如果tree被最高级的定语(tallest)修饰,that可以省略但不能用which来代替。 再问： 变成trees planted grow very well。那为什么不是主语从句，that指树，做主语啊 再答： The trees that they planted grow very well。 主语：The trees 谓语：grow 状语：very well 定语从句：(that) they planted, 修饰主语The trees