Telephone systems are at the heart of business, whether it is a standard land line, mobile phones, voicemail, teleconferencing, or Internet phone software.?是什么意思_Telephone systems are at the heart of business, whether it is a standard land line, mobile phones, voicemail, teleconferencing, or Internet phone software.?在線(xiàn)翻譯_英語(yǔ)_讀音_用法_例句