Pfizer denies that it acted improperly, but the catastrophe helps to explain why people in Kano became suspicious of the polio vaccine several years later.是什么意思_Pfizer denies that it acted improperly, but the catastrophe helps to explain why people in Kano became suspicious of the polio vaccine several years later.在線(xiàn)翻譯_英語(yǔ)_讀音_用法_例句