BEIJING – Chinese authorities have asked residents in two cities south of Beijing to stay home for seven days as they try to stamp out a COVID-19 outbreak in which more than 300 people have tested positive in the past week.The cities of Shijiazhuang and Xingtai in Hebei province are restricting people to their communities and villages and have banned gatherings, according to notices they posted on social media.Hebei reported 14 more confirmed cases in the latest 24-hour period, bringing the total in the ongoing outbreak to 137.