VOA慢速英语:我们什么时候能获得新冠疫苗？

trial –n. a test of the quality, effectiveness or safety of something like a medicine or treatment

capacity –n. the ability to produce a certain amount of something within a certain time

dose –n. the amount of medicine or treatment needed to be taken at one time to get the correct result

queue –n. a line of things or people that are waiting to move forward

global –adj. something that involves the entire world