知乎，让每一次点击都充满意义 —— 欢迎来到知乎，发现问题背后的世界。 In 1951, the British Board of Film Censors released the X certification to indicate a film was "really graphic." Although this at first referred to violence and lousy language and intercourse, "X-rated" was co-opted from the porn industry and is now shorthand for sexually explicit product. https://coingenius.news/ai-innovations-from-superbug-solutions-to-smart-kayaking-and-beyond/