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 Movie Censors launched the X certification to point a movie was "very graphic." However this initially referred to violence and undesirable language and also sex, "X-rated" was co-opted by the porn industry and it is now shorthand for sexually express https://coingenius.news/revolutionizing-healthcare-the-impact-of-responsible-ai-integration-and-iot-innovations/