He says--and here's that Yeatsian word "all" again--he says: When I try to put all into a phrase I say, "Man can embody truth but he cannot know it."

他说，又是他涵盖一切的词：,当我想用一句话概括时，我说，人可以表现他不理解的真理“

耶鲁公开课 - 现代诗歌课程节选

You cannot say, "I never heard of it. I don't know where it came from."

你就不能再说,"我从没听说过,我不知道它是怎么来的"

耶鲁公开课 - 基础物理课程节选