presided over a fraying of the nation's socialist safety net. China now faces a multitude of social woes usually seen in more-developed economies better equipped to handle these chanllenges. It is growing old before it grows rich ---- bringing about an explosion of elderly Chinese even as the government has presided over a fraying of the nation's socialist safety net. I have difficulty in understanding "has presided over a fraying of the nation's socialist safety net", especially the phrase "preside over" and the word "fraying" here. thank you for your help and your time