China has reported zero domestically transmitted Covid-19 cases for three straight days, but the nation is bracing for more imported cases from overseas. The number of infections from abroad stood at 269 cases as of March 20, 2020, according to China’s National Health Commission. Meanwhile, some health experts said China’s coronavirus infection figures must be treated with caution, because there could be undiagnosed people who could spread the novel coronavirus to others. (Photo: China Daily…