The dress whose color is red is bought by my mom. 红色那件裙子是我妈妈买的。

我想问，whose 在这里作定语，是不是指它指代的是 color is red，而不是 the dress。

这个句子的成份划分能讲下吗？

回答如下：

▲关系代词whose 引导定语从句，在从句中只能充当定语作用

whose + 名词=the +名词+ of which / of which + the +名词

The dress whose color is red is bought by my mom

=The dress the color of which is red is bought by my mom

=The dress of which the color is red is bought by my mom

▲成分划分

主句主语：the dress

修饰主句主语的定语从句：whose color is red

主句谓语：is bought

主句状语：by my mom

▲定语从句语法结构

主语：whose color

系动词：is

表语：red