VOA慢速英语:羊驼有助于制造新冠病毒疫苗

antibody – medical n. a substance produced by the body to fight disease

principle – n. a basic truth or theory : an idea that forms the basis of something : a law or fact of nature that explains how something works or why something happens

mutate – v. to cause (a gene) to change and create an unusual characteristic in a plant or animal : to cause mutation in (a gene)

pandemic – n. occurring over a wide geographic area and affecting an exceptionally high proportion of the population