The dictionary___ is sold out in the bookshop 

A. you need 

B. what you need 

C. which you need it 

D. that you need it 

这道题为什么选A，麻烦讲解一下。

   【答】这道题选A是正确的。The dictionary you need  is sold out in the bookshop. = The dictionary that (which) you need  is sold out in the bookshop. 你需要的那本词典书店里买完了。[ 划底线部分是定语从句，that (which)是关系代词，在从句中作 need 的宾语，可以省略。该定语从句修饰的先行词是 dictionary ] 

    is sold out 是动词 sell 的被动语态。