Experts are worried some Americans are letting up too early -- at a critical time when looming dangers are threatening to wipe out the progress the US has made in its battle against Covid-19.
원문출처 : https://www.cnn.com/2021/03/16/health/us-coronavirus-tuesday/index.html
원문출처 : https://www.cnn.com/2021/03/16/health/us-coronavirus-tuesday/index.html