It belongs to a group of viruses that includes the smallpox virus( variola), the virus used in the smallpox vaccine( vaccinia), and the cowpox virus.是什么意思_It belongs to a group of viruses that includes the smallpox virus( variola), the virus used in the smallpox vaccine( vaccinia), and the cowpox virus.在線(xiàn)翻譯_英語(yǔ)_讀音_用法_例句