这确实是很令人费解的一件事，我也不知道这是为什么。

This is indeed a very puzzling thing, I do not know why.

youdao

海曼在一次访谈中表示：“说实话，我也不知道这是为什么。”

"I honestly don't know why this is," Heiman said in an interview.

youdao

我不知道为什么会有这样的想法，我也不知道这是好还是坏。

I don't know why will have thus of viewpoint, I also don't know this to be good or bad.

youdao

The third derivative, unfortunately, was never given a name, and I don't know why.

遗憾的是三阶导数没有专门的名称,我也不知道这是为什么

耶鲁公开课 - 基础物理课程节选