VOA慢速英语:美国部分州让医学生帮忙注射新冠疫苗

incentive – n. something that encourages a person to do something or to work harder

first responder – n. someone trained to respond to an emergency.

dose – n. the amount of a medicine or drug that is taken at one time

crucial – adj. extremely important

essential – adj. extremely important and necessary

tangible – adj. easily seen or recognized

frontline – n. an area involving action and conflict

supervision – n. the action or process of watching and directing what someone does or how something is done

encourage –v. to make (someone) more determined, hopeful, or confident