Greenwood has been the source of controversy, having been sent home from England duty last week after breaching Covid-19 guidelines, an incident for which he also had to apologise.Greenwood has now urged others not to follow his example, with the teenager having since been told of the risks of nitrous oxide.In a statement from United, Greenwood said: "I have now been made aware of the health risks associated with this practice and accept that even trying it, as shown in these historical