"Li ĉiam komentas pri aferoj pri kiuj li scias nenion."

Translation: He always comments on things about which he knows nothing.

[Druif]

I wrote "He always comments about things that he knows nothing of."

"Of" had to be "about".
"He knows nothing of me." is a good sentence. Why can't it be used in this sentence?

[PatriciaJH]

Seems OK; sounds very British, though! Report it.

[FredCapp]

I had a similar problem. "Of which he knows nothing" was dinged at the "of."

I reported it.

And I also found myself thinking about BookFace.

[mizinamo]

I would prefer "He knows nothing about me".