I have no idea where the journalist could have got his information from.这是什么从句?

I have no idea where the journalist could have got his information from.这是什么从句?
I have no idea where the journalist could have got his information from.这是什么从句?

I have no idea where the journalist could have got his information from.这是什么从句?
同位语从句.
在have no idea后接的是同位语从句,相当于：don't know,如果改成don't know就是宾语从句了.
I have no idea what he is doing=I don't know what he is doing.

是同位语从句！例子中这些个从句都是修饰前面的idea。只有动词/介词/形容词才可以在后面跟宾语从句。

where the journalist could have got his information from. 是idea同位语从句。