Which questions do you not know the answers to?

Which ones do you need more information on?

网友句子中的句末介词不能没有，因为句首的 which questions 和 which ones 分别是句末介词 to, on 的宾语。要是没有这个介词，它作谁的宾语呢？

I don’t know the answers to these three questions.

I need more information on these three questions.

如果对加粗的部分提问，你看看是不是刚好得到你的两个问句？