Diphtheria is generally not a problem in tropical countries. It is usually characterized by a patch or patches of a grayish membrane in the throat.是什么意思_Diphtheria is generally not a problem in tropical countries. It is usually characterized by a patch or patches of a grayish membrane in the throat.在線(xiàn)翻譯_英語(yǔ)_讀音_用法_例句