You know perfectly well what happened.

你完全清楚发生了什么。

《柯林斯英汉双解大词典》

You know perfectly well what I mean.

我的意思你是一清二楚的。

《牛津词典》

Come, come, Miss Jones, you know perfectly well what I mean.

得啦，得啦，琼斯小姐，你完全知道我的意思。

《牛津词典》

But is has another sense which is not a rhetorical sense, because metaphor is sort of the heart of rhetoric, the rhetorical sense A is B--when, by the way, A we know perfectly well that A is not B. How can A be B? A is only A.

但是is有另外一个意思，修辞之外的一种意思，因为暗喻差不多可以说是修辞的中心，修辞中所说的A是B，顺便说一下，我们十分清楚地知道A不是B，A怎么能是B呢，A就是。

耶鲁公开课 - 文学理论导论课程节选

"They know perfectly well what happened and so do we, " he said at a hastily called news conference.

NPR: Tensions Up In Venezuela After Polls Close

Most managers know perfectly well that they have to do better.

ECONOMIST: Business and the Internet

Officials know perfectly well that passengers will already have imbibed all the fructarian juices imaginable on the ground and will welcome the alternative of these expensively imported, highly calorific pop drinks to keep their energy levels up during random in-flight activities like mass seat changes and locating serviceable toilets.

CNN: From Our Correspondent: On a Magical Hill