translation.en: It means that after a trauma, without question, we lose our "unbearable lightness of being," that sense of immortality that keeps us here -- meaning, if we're here, we almost feel like we're immortal, which we're not, but if we didn't believe that, we'd say, "What's the point of it all?"
translation.zh: 这意味着在一次创伤以后， 毫无疑问，我们失去那种”生命不能承受之轻“的感觉， 那种使我们伫立在这里的，不朽的意识-- 这意味着，我们的存在让我们几乎觉得这是不朽的，虽然并不是这样， 但我们并不相信，我们会说，”那这一切又有什么意义呢？“