I'm afraid I don't quite follow you.的结构

问题描述:

I'm afraid I don't quite follow you.的结构
请分析下I'm afraid I don't quite follow you.的结构
特别是I don't quite follow you.是一个什么从句,修饰什么.麻烦详尽些

I don't quite follow you一般视作状语从句,说明afraid(恐怕)的理由.
也有一部分语法家认为少数形容词在作表语时可以跟宾语从句,这类形容词有sure,sorry,glad,aware...等等.这句话的意思:
“我恐怕跟不上你的意思” 也就是“我听不大明白”