Question

Do you have any ideas ________ is actually going on in the classroom?

1. A.
   that
2. B.
   what
3. C.
   as
4. D.
   Which

Answer 1

B
解析：
主要测试同位语从句。有句子语境可以晓得句子意思为：你知道教室里实际在发生什么事吗？另外所选答案还要充当双重作用：引导句子还要做从句的主语。故此答案一目了然。