I knew nothing of his business dealings.

我对他生意上的事一概不知道。

《牛津词典》

I swear on my honour that I knew nothing about this.

我以人格担保我根本不知道这件事。

《牛津词典》

I can say in all sincerity that I knew nothing of these plans.

我可以十分坦诚地说，这些计划我一无所知。

《牛津词典》

I do not hold any animosity. But I tell Obasanjo today, and I am sure he knows it, that he lied to the world when he said that I was escaping and he knew nothing about it.

VOA: standard.2009.11.10

Senator PATRICK LEAHY (Democrat, Vermont): I knew nothing about it until I saw the story.

NPR: Sen. Leahy Looking for Answers on NSA Operations

I'm so focused on making sure I have the answers to your questions, I knew nothing about the transit of Venus.

WHITEHOUSE: Press Briefing

Sadly, I knew nothing about dairy bulls and the milk industry.

FORBES: Barnacles, Diamonds and Cows: 5 Startup Failures--My 5 Lessons Learned