VOA慢速英语:mRNA疫苗技术的下一个目标是攻克癌症

immune system –n. the system that protects your body from diseases and infections

tumor –n. a mass of tissue found in or on the body that is made up of abnormal cells

bold –adj. not afraid of danger or difficult situations

extraordinary –adj. extremely good or impressive

obstacle –n. a problem that makes it difficult to reach a goal; a barrier

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

rigid –adj. unwilling to lower requirements or compromise quality

credit –n. praise or special attention that is given to someone for doing something or for making something happen

acknowledge –n. the act of showing that you know, admit, or accept that something exists or is true