I know whereof you speak.

我知道你在说关于什么。

The reasons whereof he spoke were not convincing.

他所说的那些理由并不令人信服。

The details whereof we discussed are crucial to the project.

我们讨论的那些细节对项目至关重要。

The book, whereof the title is unknown, is very interesting.

那本书的标题未知，但非常有趣。

The document, whereof you are in possession, is confidential.

你持有的那份文件是机密的。

He didn't know whereof he talked about.

他不知道自己说了些什么。

They have something whereof they are proud.

他们自有其所骄傲者在。

Ancient pottery whereof many examples are lost.

许多样品都不见了的古代陶器。

What is your substance, whereof are you made.

你的本质是什么，用什么造成。

Whereof one cannot speak, thereof one must be silent.

对于不能说的人们必须保持沉默。