Healthy persons generally experience mild symptoms when they get these infections. However, some persons are more susceptible to these infections and may have unusually severe illness.是什么意思_Healthy persons generally experience mild symptoms when they get these infections. However, some persons are more susceptible to these infections and may have unusually severe illness.在線(xiàn)翻譯_英語(yǔ)_讀音_用法_例句