Periods when diseases spread around the world are called pandemics.疾病在全世界范围内传播时期称为大流行.Since then, there have been a total of eight cholera pandemics.从那时开始, 霍乱大流行总共爆发过8次.Previous pandemics have been characterized by waves...

n.（全国或全球性）流行病，大流行病( pandemic的名词复数 )...

pandemics的音标：...