今天我们要学的词是 circulate. Circulate 动词，意思是传播。流感疫苗是如何研制的?Flu viruses constantly mutate, and the vaccine is changed every year based on what scientists see circulating. 流感病毒不断变异，所以科学家每年都要根据眼下正在流行的病毒来研制疫苗。The University of Oklahoma is investigating a video circulating on social media allegedly showing members of a fraternity chanting racist language. 俄克拉荷马大学对社交媒体上流传的一段视频展开调查，据悉视频上显示了该大学一个兄弟会成员高喊种族歧视的语言。好的，今天我们学习的词是 circulate, circulate, circulate...