VOA慢速英语:专家称新冠疫苗加强针在未来几年内都需要注射

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

regular – adj. happening over and over again at the same time or in the same way

immunity – n. the power to keep yourself from being affected by a disease

dose – n. the amount of medication to be taken at one time

variant – n. different in some way from others of the same kind

sequence – v. a group of things that come one after the other

humble – adj. not thinking of yourself as better than others