Question

Do you have an idea ________ is actually going on in the classroom?

[　　]

A．

that

B．

what

C．

as

D．

which

Answer 1

答案：B
解析：

本题的意思是“你知道教室里到底正在进行什么活动”，idea之后跟同位语从句，选项引导同位语从句，还要在从句中作主语，身兼二职，只有B项能满足这一要求。